Explanation:
Dark Energy. Dark Energy is a hypothetical form of energy that exerts a negative, repulsive pressure, behaving like the opposite of gravity. It has been hypothesised to account for the observational properties of distant type Ia supernovae, which show the universe going through an accelerated period of expansion
Electric charge is distributed over the disk x2 + y2 ≤ 4 so that the charge density at (x, y) is rho(x, y) = 2x + 2y + 2x2 + 2y2 (measured in coulombs per square meter). Find the total charge on the disk.
Answer:
the total charge on the disk 256pi Coulombs
Explanation:
Pls see attached file
A student is trying to decide what to wear.His bedroom is at 20.0 °C.His skin temperature is 35.0 °C.The area of his exposed skin is 1.50 m².People all over the world have skin that is dark in the infrared,with emissivity about 0.900.Find the net energy transfer from his body by radiation in 10.0 min.
Answer:
vgghcgkxcjpfiffj,ncfzfzujfzxxxoifkc xuzrusdoxTXcxgifdhh
A parallel–plate capacitor is initially charged by connecting it to a battery. The battery is then disconnected. If the distance between the plates is increased, what happens to the charge on the capacitor and the voltage across it?
a. The charge remains fixed and the voltage decreases.
b. The charge decreases and the voltage remains fixed.
c. The charge remains fixed and the voltage increases.
d. The charge decreases and the voltage increases.
Answer:
t the battery of potential difference V be used to charge the capacitor of capacitance C.
∴ the charge stored in the capacitor q=CV
Now the battery is disconnected, so the the charge of the capacitor becomes constant
i.e q=constant OR CV=constant .............(1)
Capacitance of parallel plate capacitor C=
d
Aϵ
o
So if the distance between the plates is increased, then the capacitance will decrease which is compensated by the increase in voltage across the capacitor according to equation (1).
Also the energy stored in the capacitor E=
2C
q
2
⟹E∝
C
1
(∵q=constant)
Thus energy will increase due to the decrease in capacitance.
Explanation:
Electromagnetic waves are traveling in the vacuum of space. Calculate the wavelengths of these electromagnetic waves with the following frequencies. (Enter the first wavelength in pm and the second wavelength in cm.)
(a) 2.00 x 1019 Hz
(b) 4.50 x109 Hz
Answer:
(a) 1.5×10⁻¹¹ m.
(b) 6.7×10⁻² m
Explanation:
Note: All Electromagnetic wave travels in with the same speed, which 3×10⁸ m/s
(a) Give a frequency of 2.00×10¹⁹ Hz.
Using the equation of a wave,
V = λf................ Equation 1
Where V = Speed of electromagnetic wave, λ = wavelength, f = frequency.
make λ the subject of the equation
λ = V/f................. Equation 2
Given: f = 2.00×10¹⁹ Hz.
Constant: v = 3×10⁸ m/s.
Substitute into equation 2
λ = 3×10⁸/2.00×10¹⁹
λ = 1.5×10⁻¹¹ m.
(b) Similarly using
λ = v/f
Given: f = 4.5×10⁹ Hz, and v = 3×10⁸ m/s.
Substitute these values into equation 2 above.
λ = 3×10⁸/4.5×10⁹
λ = 6.7×10⁻² m
Which scientist proved experimentally that a shadow of the circular object illuminated 18. with coherent light would have a central bright spot?
A. Young
B. Fresnel
C. Poisson
D. Arago
Answer:
Your answer is( D) - Arago
The electron beam inside a television picture tube is 0.40 {\rm mm} in diameter and carries a current of 50 {\rm \mu A}. This electron beam impinges on the inside of the picture tube screen.
How many electrons strike the screen each second?
The electrons move with a velocity of 4.0\times10^7\;{\rm m/s}. What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.0 {\rm mm}?
Each electron transfers its kinetic energy to the picture tube screen upon impact. What is the power delivered to the screen by the electron beam? (Hint: What potential difference produced the field that accelerated electrons? This is an emf.)
Answer:
A.3.13x10^14 electrons
B.330A/m²
C.9.11x10^5N/C
D. 0.23W
.pls see attached file for explanations
wrench is to Hammer as
Answer:
Pencil is to pen
Step by step explanation:
They are similar items, as they are both tools, but are different as to how they function.
A centrifugal pump is operating at a flow rate of 1 m3/s and a head of 20 m. If the specific weight of water is 9800 N/m3 and the pump efficiency is 85%, the power required by the pump is most nearly:
Answer:
The power required by the pump is nearly 230.588 kW
Explanation:
Flow rate of the pump Q = 1 m^3/s
the head flow H = 20 m
specific weight of water γ = 9800 N/m^3
efficiency of the pump η = 85%
First note that specific gravity of water is the product of the density of water and acceleration due to gravity.
γ = ρg
where ρ is density. For water its value is 1000 kg/m^3
g is the acceleration due to gravity = 9.81 m/s^2
The power to lift this water at this rate will be gotten from the equation
P = ρgQH
but ρg = γ
therefore,
P = γQH
imputing values, we'll have
P = 9800 x 1 x 20 = 196000 W
But the centrifugal pump that will be used will only be able to lift this amount of water after the efficiency factor has been considered. The power of pump needed must be greater than this power.
we can say that
196000 W is 85% of the power of the pump power needed, therefore
196000 = 85% of [tex]P_{p}[/tex]
where [tex]P_{p}[/tex] is the power of the pump needed
85% = 0.85
196000 = 0.85[tex]P_{p}[/tex]
[tex]P_{p}[/tex] = 196000/0.85 = 230588.24 W
Pump power = 230.588 kW
Two long parallel wires separated by 4.0 mm each carry a current of 24 A. These two currents are in the same direction. What is the magnitude of the magnetic field at a point that is between the two wires and 1.0 mm from one of the two wires
Answer:
Explanation:
Magnetic field at a a point R distance away
B = μ₀ / 4π X 2I / R where I is current
Magnetic field due to one current
= 10⁻⁷ x 2 x 24 / 1 x 10⁻³
48 x 10⁻⁴ T
Magnetic field due to other current
= 10⁻⁷ x 2 x 24 / 3x 10⁻³
16 x 10⁻⁴ T
Total magnetic field , as they act in opposite direction, is
= (48 - 16 ) x 10⁻⁴
32 x 10⁻⁴ T .
Isaac drop ball from height og 2.0 m, and it bounces to a height of 1.5 m what is the speed before and after the ball bounce?
Explanation:
It is given that, Isaac drop ball from height of 2.0 m, and it bounces to a height of 1.5 m.
We need to find the speed before and after the ball bounce.
Let u is the initial speed of the ball when he dropped from height of 2 m. The conservation of energy holds here. So,
[tex]\dfrac{1}{2}mu^2=mgh\\\\u=\sqrt{2gh} \\\\u=\sqrt{2\times 9.8\times 2} \\\\u=6.26\ m/s[/tex]
Let v is the final speed when it bounces to a height of 1.5 m. So,
[tex]\dfrac{1}{2}mv^2=mgh\\\\v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 1.5} \\\\v=5.42\ m/s[/tex]
So, the speed before and after the ball bounce is 6.26 m/s and 5.42 m/s respectively.
What are three ways synthetic polymers affect the environment?
Answer:
-Some synthetic polymers use materials from Earth that are nonrenewable.
-They can end up as waste products that sometimes can’t be recycled.
-They sometimes release toxins into the environment.
Explanation:
Synthetic polymers are types of polymers that are man made, that is they are polymers that are made in the labs or industries from chemical substances.
Such polymers include nylon, polyester, and polyethylene among others. These polymers are used to make many clothes and plastics that we use and see around.
Synthetic polymers have a range of disadvantages which includes. being non-biodegradable, these polymers and especially plastics may end up as waste products and pollutes the environment and end up in livers and lakes and this would be toxic for aquatic animals.
The temperature gradient between the core of Mars and its surface is approximately 0.0003 K/m. Compare this temperature gradient to that of Earth. What can you determine about the rate at which heat moves out of Mars’s core compared to Earth?
Answer:
The temperature gradient between the core of Mars and its surface is lower than that on Earth. So, heat moves outward more slowly on Mars than on Earth.
Explanation:
Answer:
The temperature gradient between the core of Mars and its surface is lower than that on Earth. So, heat moves outward more slowly on Mars than on Earth.
Explanation:
Edmentum sample answer
Two slits are separated by 0.370 mm. A beam of 545-nm light strikes the slits, producing an interference pattern. Determine the number of maxima observed in the angular range−26.0° ≤ θ ≤ 26.0°.
Answer:
There are 586maxima
Explanation:
Pls see attached file
An apple falls from a tree and hits your head with a force of 9J. The apple weighs 0.22kg. How far did the apple fall?
Answer:
The apple fell at a distance of 4.17 m.
Explanation:
Work is defined as the force that is applied on a body to move it from one point to another. When a force is applied, an energy transfer occurs. Then it can be said that work is energy in motion.
When a net force is applied to the body or a system and this produces displacement, then that force is said to perform mechanical work.
In the International System of Units, work is measured in Joule. Joule is equivalent to Newton per meter.
The work is equal to the product of the force by the distance and by the cosine of the angle that exists between the direction of the force and the direction that travels the point or the object that moves.
Work=Force*distance* cosine(angle)
On the other hand, Newton's second law says that the acceleration of a body is proportional to the resultant of forces on it acting and inversely proportional to its mass. This is represented by:
F=m*a
where F is Force [N], m is Mass [kg] and a Acceleration [m / s²]
In this case, the acceleration corresponds to the acceleration of gravity, whose value is 9.81 m / s². So you have:
Work= 9 JF=m*a=0.22 kg*9.81 m/s²= 2.1582 Ndistance= ?angle=0 → cosine(angle)= 1Replacing:
9 J= 2.1582 N* distante* 1
Solving:
[tex]distance=\frac{9J}{2.1582 N*1}[/tex]
distance= 4.17 m
The apple fell at a distance of 4.17 m.
When a 20.0-ohm resistor is connected across the terminals of a 12.0-V battery, the voltage across the terminals of the battery falls by 0.300 V. What is the internal resistance of this battery
Answer:
The internal resistance is [tex]r = 0.5 \ \Omega[/tex]
Explanation:
From the question we are told that the resistance of
The resistance of the resistor is [tex]R = 20.0\ \Omega[/tex]
The voltage is [tex]V = 12.0 \ V[/tex]
The magnitude of the voltage fall is [tex]e = 0.300\ V[/tex]
Generally the current flowing through the terminal due to the voltage of the battery is mathematically represented as
[tex]I = \frac{V}{R}[/tex]
substituting values
[tex]I = \frac{12.0 }{20 }[/tex]
[tex]I = 0.6 \ A[/tex]
The internal resistance of the battery is mathematically represented as
[tex]r = \frac{e}{I}[/tex]
substituting values
[tex]r = \frac{0.300}{ 0.6 }[/tex]
[tex]r = 0.5 \ \Omega[/tex]
The internal resistance of the battery is 0.5 ohms.
To calculate the internal resistance of the battery, we use the formula below
Formula:
(V/R)r = V'............. Equation 1Where:
V = Voltage across the terminal of the batteryR = Resistance connected across the batteryr = internal resistance of the batteryV' = voltage drop of the battery.Make r the subject of the equation
r = V'R/V............ Equation 2From the question,
Given:
V = 12 VR = 20 ohmsV' = 0.3 VSubstitute these values into equation 2
r = (0.3×20)/12r = 6/12r = 0.5 ohms.Hence, The internal resistance of the battery is 0.5 ohms.
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A conducting sphere contains positive charge distributed uniformly over its surface. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. (There may be more than one correct choice.)
Hello. This question is incomplete. The full question is:
A conducting sphere contains positive charge distributed uniformly over its surface. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. (There may be more than one correct choice.)
A) The potential is lowest, but not zero, at the center of the sphere. B) The potential at the center of the sphere is zero. C) The potential at the center of the sphere is the same as the potential at the surface. D) The potential at the surface is higher than the potential at the center. E) The potential at the center is the same as the potential at infinity
Answer:
C) The potential at the center of the sphere is the same as the potential at the surface.
Explanation:
When a conductive sphere has charges that distribute evenly on its surface, it means that its interior has a zero charge cap. As a result, the outside of this sphere has a charge distribution that will be the same if the center of the sphere were charged. In this way, the center and the surface of the sphere become identical in relation to the point charge potential. In other words, this means that the null interior of the sphere has a constant potential that makes the distribution of charges within the sphere exactly equal to the distribution of charges outside the sphere.
The statement that should be true regarding the sphere is The potential at the center of the sphere.
Potential at the sphere center:Here the normal formula should be used i.e. kq/R that should be determined by considering the potential at infinity also it does not contain any intervening dielectric like zero.
Also,
kq/R+c,
Here c is constant is necessary to fit with respect to the zero potential.
Hence, The statement that should be true regarding the sphere is The potential at the center of the sphere.
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Three point charges (some positive and some negative) are fixed to the corners of the same square in various ways, as the drawings show. Each charge, no matter what its algebraic sign, has the same magnitude. In which arrangement (if any) does the net electric field at the center of the square have the greatest magnitude?
Answer:
The magnitude of the net field located at the center of the square is the same in every of arrangement of the charges.
Astronomers have recently observed stars orbiting at very high speeds around an unknown object near the center of our galaxy. For stars orbiting at distances of about 1014 m from the object, the orbital velocities are about 106 m/s. Assume the orbits are circular, and estimate the mass of the object, in units of the mass of the sun (MSun = 2x1030 kg). If the object was a tightly packed cluster of normal stars, it should be a very bright source of light. Since no visible light is detected coming from it, it is instead believed to be a supermassive black hole.
Answer:
The mass of the object is 745000 units of the sun
Explanation:
We know that the centripetal force with which the stars orbit the object is represented as
[tex]F_{c}[/tex] = [tex]\frac{mv^{2} }{r}[/tex]
and this centripetal force is also proportional to
[tex]F_{c}[/tex] = [tex]\frac{kMm}{r^{2} }[/tex]
where
m is the mass of the stars
M is the mass of the object
v is the velocity of the stars = 10^6 m/s
r is the distance between the stars and the object = 10^14 m
k is the gravitational constant = 6.67 × 10^-11 m^3 kg^-1 s^-2
We can equate the two centripetal force equations to give
[tex]\frac{mv^{2} }{r}[/tex] = [tex]\frac{kMm}{r^{2} }[/tex]
which reduces to
[tex]v^{2}[/tex] = [tex]\frac{kM}{r}[/tex]
and then finally
M = [tex]\frac{rv^{2} }{k}[/tex]
substituting values, we have
M = [tex]\frac{10^{14}*(10^{6})^{2} }{6.67*10^{-11} }[/tex] = 1.49 x 10^36 kg
If the mass of the sun is 2 x 10^30 kg
then, the mass of the the object in units of the mass of the sun is
==> (1.49 x 10^36)/(2 x 10^30) = 745000 units of sun
A small solid conductor with radius a is supported by insulating, nonmagnetic disks on the axis of a thin-walled tube with inner radius b. The inner andouter conductors carry equal currents i in oppositedirections.
Required:
a. Use Ampere's Law to find the magnetic field at any pointin the volume between the conductors.
b. Write the expression for the flux dΦB through anarrow strip of length l parallel to the axis , of width dr, at a distancer from the axis of the cableand lying in a plane containing the axis.
c. Integrate your expression from part B over the volumebetween the two conductors to find the total flux produced by acurrent i in the central conductor.
d. Use equation U=(1/2)LI2 to calculate the energy stored in the magnetic field for alength l of the cable.
Answer:
Pls see attached file
Explanation:
A block with a mass of 0.28 kg is attached to a horizontal spring. The block is pulled back from its equilibrium position until the spring exerts a force of 1.0 N on the block. When the block is released, it oscillates with a frequency of 1.2 Hz. How far was the block pulled back before being released?
Answer:
Explanation:
For spring
[tex]n=\sqrt{\frac{k}{m} }[/tex]
where n is frequency of oscillation and k is force constant and m is mass
Putting the values
[tex]1.2=\sqrt{\frac{k}{.28} }[/tex]
k = .4032 N/m
F= k x
where F is force , k is force constant and x is extension
Putting the given values
1 = .4032 x
x = 2.48 m
An aluminum cup of mass 150 g contains 800 g of water in thermal equilibrium at 80.0°C. The combination of cup and water is cooled uniformly so that the temperature decreases by 1.50°C per minute. At what rate is energy being removed by heat? Express your answer in watts.
Answer:
Heat Flow Rate : ( About ) 87 W
Explanation:
The heat flowing out of the system each minute, will be represented by the following equation,
Q( cup ) + Q( water ) = m( cup ) [tex]*[/tex] c( al ) [tex]*[/tex] ΔT + m( w ) [tex]*[/tex] c( w ) [tex]*[/tex] ΔT
So as you can see, the mass of the aluminum cup is 150 grams. For convenience, let us convert that into kilograms,
150 grams = .15 kilograms - respectively let us convert the mass of water to kilograms,
800 grams = .8 kilograms
Now remember that the specific heat of aluminum is 900 J / kg [tex]*[/tex] K, and the specific heat of water = 4186 J / kg [tex]*[/tex] K. Therefore let us solve for " the heat flowing out of the system per minute, "
Q( cup ) + Q( water ) = .15 [tex]*[/tex] ( 900 J / kg [tex]*[/tex] K ) [tex]*[/tex] 1.5 + .8 [tex]*[/tex] ( 4186 J / kg [tex]*[/tex] K ) [tex]*[/tex] 1.5,
Q( cup ) + Q( water ) = 5225.7 Joules
And the heat flow rate should be Joules per minute,
5225.7 Joules / 60 seconds = ( About ) 87 W
Which is true about refraction from one material into a second material with a greater index of refraction when the incident angle is, say, 30º? At the interface, the ray bends toward the normal.
Answer:
Explanation:
Refraction is defined as the bending of light rays as an incident ray pass from one medium to another. If the incident ray is passing from the media with low refractive index to a greater refractive index, the refracted ray tends to bend away from the normal.
Refractive index is the ratio of the sin of angle of incidence to the sine of angle of refraction.
n = sin i/sin r
For us to have a greater index of refraction, the denominator must be lesser than the numerator. This means that the angle of refraction must be smaller and if the angle of refraction must get smaller, this means that the refracted ray must bend towards the normal
A negatively charged object is located in a region of space where the electric field is uniform and points due north. The object may move a set distance d to the north, east, or south. Write the three possible movements by the change in electric potential energy (Ue) of the object.
Answer:
the three possible movements by the change in electric potential energy (Ue) of the object are NORTH EAST SOUTH
Explanation:
This is because When the object moves south, the force is in the direction of the displacement, and positive work is done with decreasing electric potential energy.
The opposite is true if the particle moves north—that is, negative work is done with increasing electric potential energy.
No work is done and the electric potential energy is constant if the motion is perpendicular to the electric field.
What do Equations 1 and 2 predict will happen to the single-slit diffraction pattern (intensity, fringe width, and fringe spacing) as the slit width is increased.
Equation 1:
Sinθ = mλ/ω
Equaiton 2:
I= Io [Sinθ (πωλ/πωλ/Rλ)
Answer:
the firtz agrees with the expression for the shape of the curve of diracion of a slit
Explanation:
The diffraction phenomenon is described by the expression
a sin θ = m λ
where a is the width of the slit, t is the angle from the center of the slit, l is the wavelength and m is an integer that corresponds to the maximum diffraction.
the previous equation qualitatively describes the curve of the diffraction phenomenon the equation takes the form
I = I₀ [(sin ππ a y / R λ) / π a y / Rλ]²
I = I₀ ’[sin π a y /Rλ]²
I₀ ’= I₀ / (π a y /Rλ)²
By reviewing the two expressions given
equation 1
w sin θ = m λ
where w =a w is the slit width
we see that the firtz agrees with the expression for the shape of the curve of diracion of a slit
Equation 2
the squares are missing
Unpolarized light of intensity I0 = 950 W/m2 is incident upon two polarizers. The first has its polarizing axis vertical, and the axis of the second is rotated θ = 65° from the vertical.
Required:
a. What is the intensity of the light after it passes through the first polarizer in W/m2?
b. What is the intensity of the light after it passes through the second polarizer in W/m2?
Answer:
Intensity of the light (first polarizer) (I₁) = 425 W/m²
Intensity of the light (second polarizer) (I₂) = 75.905 W/m²
Explanation:
Given:
Unpolarized light of intensity (I₀) = 950 W/m²
θ = 65°
Find:
a. Intensity of the light (first polarizer)
b. Intensity of the light (second polarizer)
Computation:
a. Intensity of the light (first polarizer)
Intensity of the light (first polarizer) (I₁) = I₀ / 2
Intensity of the light (first polarizer) (I₁) = 950 / 2
Intensity of the light (first polarizer) (I₁) = 425 W/m²
b. Intensity of the light (second polarizer)
Intensity of the light (second polarizer) (I₂) = (I₁)cos²θ
Intensity of the light (second polarizer) (I₂) = (425)(0.1786)
Intensity of the light (second polarizer) (I₂) = 75.905 W/m²
A narrow beam of light containing red (660 nm) and blue (470 nm) wavelengths travels from air through a 2.60 cm thick flat piece of crown glass and back to air again. The beam strikes the glass at a 28.0° incident angle.
A) At what angles do the two colors emerge?
B) By what distance are the red and blue separated when they emerge?
Answer:
A: 28°
B. 1x10^-3M
Explanation:
See attached file
A solenoid of 200 turns carrying a current of 2 A has a length of 25 cm. What is the magnitude of the magnetic field at the center of the solenoid?
Answer:
Explanation:
For magnetic field in a solenoid , the formula is
B = μ₀ n I
Where n is number of turns per unit length and i is current
Putting the values
B = 4π x 10⁻⁷ x (200 / .25) x 2
= 2.00 x 10⁻³ T
Suppose a space vehicle with a rest mass of 150 000 kg travels past the International Space Station at a constant speed of 2.6 x 108 m/s with respect to the I.S.S. When an observer on the I.S.S. measures the moving vehicle, her measurement of the space vehicle length is 25.0 m. Determine the relativistic mass of the space vehicle. Determine the length of the space vehicle as measured by an astronaut on the space vehicle.
Answer:
m = 300668.9 kg
L₀ = 12.47 m
Explanation:
The relativistic mass of the space vehicle is given by the following formula:
[tex]m = \frac{m_{0}}{\sqrt{1-\frac{v^{2} }{c^{2}} } }[/tex]
where,
m = relativistic mass = ?
m₀ = rest mass = 150000 kg
v = relative speed = 2.6 x 10⁸ m/s
c = speed of light = 3 x 10⁸ m/s
Therefore
[tex]m = \frac{150000kg}{\sqrt{1-\frac{(2.6 x 10^{8}m/s)^{2} }{(3 x 10^{8}m/s)^{2}} } }[/tex]
m = 300668.9 kg
Now, for rest length of vehicle:
L = L₀√(1 - v²/c²)
where,
L = Relative Length of Vehicle = 25 m
L₀ = Rest Length of Vehicle = ?
Therefore,
25 m = L₀√[1 - (2.6 x 10⁸ m/s)²/(3 x 10⁸ m/s)²]
L₀ = (25 m)(0.499)
L₀ = 12.47 m
15pts! brainliest to who answers!If Kyla picks up a grocery bag, using 10 N of force to lift it 1.5 m off the floor, how much work did Kyla do on the bag?
Explanation:
work = force x distance
w = 10 x 1.5 = 15Nm
The work done on the bag is the product of the force applied on it and the displacement of the bag. The work done to lift the bag up to 1.5 m by applying a force of 10 N is 15 J.
What is work done ?When a force applied to an object make a displacement of the body or stopes its motion, the force is said to be work done on the object. Thus, work done can be taken as the product of force and displacement.
Work done like force is a vector quantity thus characterized with magnitude and direction. Work done is equivalent to the energy required to make the object displaced.
Given the force = 10 N
displacement = 1.5 m
work done = force × displacement
w = 10 N × 1.5 m = 15 J.
Therefore, the work done on the car is 15 J.
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A motorcycle travels up one side of a hill over the top and down the other side. The crest of the hill can be considered to be a circular arc with radius of 45.0 m. Determine the maximum speed that the cycle can have while moving over the crest without losing contact with the road.
Answer:
The maximum speed of the motorcycle should be 21 m/s
Explanation:
Since the hill is considered to be a circular arc, the motorcycle will experience centripetal force that tends to flip it away from the center of the hill.
Since the motorcycle does not lose contact with the ground, it means that the weight of the motorcycle downwards just balances the centripetal force on the motorcycle.
we know that the centripetal force on the motorcycle is equal to
centripetal force = [tex]\frac{mv^{2} }{r}[/tex]
where m is the mass of the motorcycle,
v is the velocity of the motorcycle,
and r is the radius of the hill = 45.0 m
Also we now that the weight of the motorcycle is equal to
weight = mg
where m is still the mass of the motorcycle,
and g is the acceleration due to gravity = 9.81 m/s
Equating the both forces since they are equal, we'll have
[tex]\frac{mv^{2} }{r}[/tex] = mg
the mass of the motorcycle will cancel out, and we'll be left with
[tex]v^{2} = gr[/tex]
[tex]v = \sqrt{gr}[/tex]
[tex]v = \sqrt{9.81*45}[/tex]
[tex]v = \sqrt{441.45}[/tex]
[tex]v[/tex] = 21 m/s