Answer: the external agent must do work equal to -1.3 × 10⁻⁸ J
Explanation:
Given that;
Mass M1 = 7.0 kg
r = 3.0/2 m = 1.5 m
Mass M2 = 21 kg
we know that G = 6.67 × 10⁻¹¹ N.m²/kg²
work done by an external agent W = -2GM2M1 / r
so we substitute
W = (-2 × 6.67 × 10⁻¹¹ × 21 × 7) / 1.5
W = -1.96098 × 10⁻⁸ / 1.5
W = -1.3 × 10⁻⁸ J
Therefore the external agent must do work equal to -1.3 × 10⁻⁸ J
Which has more momentum, a 2000 lb car moving at 100 km/hr or a 4000 lb truck moving at 50 km/hr ?
Answer:
The truck and car have the same momentum.
Explanation:
[tex]m_1[/tex] = Mass of car = [tex]2000\ \text{lb}=2000\times0.45359237\ \text{kg}[/tex]
[tex]v_1[/tex] = Velocity of car = [tex]\dfrac{100}{3.6}\ \text{m/s}[/tex]
[tex]m_2[/tex] = Mass of truck = [tex]4000\times0.45359237\ \text{kg}[/tex]
[tex]v_2[/tex] = Velocity of truck = [tex]\dfrac{50}{3.6}\ \text{m/s}[/tex]
Momentum of car
[tex]p_1=m_1v_1\\\Rightarrow p_1=2000\times0.45359237\times \dfrac{100}{3.6}\\\Rightarrow p_1=25199.58\ \text{kg m/s}[/tex]
Momentum of the truck
[tex]p_2=m_2v_2\\\Rightarrow p_2=4000\times0.45359237\times \dfrac{50}{3.6}\\\Rightarrow p_2=25199.58\ \text{kg m/s}[/tex]
Both the truck and car have the same momentum of [tex]25199.58\ \text{kg m/s}[/tex].
A car approaches a train station with a speed of 24 m/s. A stationary train at the station sounds its horn which has a frequency of 166 Hz. What frequency of sound is heard by the car's driver
Answer:
178.5 Hz
Explanation:
Given that a car approaches a train station with a speed of 24 m/s. A stationary train at the station sounds its horn which has a frequency of 166 Hz. What frequency of sound is heard by the car's driver ?
Solution
Using doppler effect formula
F = f ( V/ V- v)
Where F = frequency of sound heard by the car
f = train frequency
V = speed of sound
v = car speed
F = 166 ( 343 ÷ ( 343 - 24 ) )
F = 166 ( 343 / 319 )
F = 166 × 1.0752
F = 178.489 Hz
F = 178.5 Hz
Therefore, the frequency of sound heard by the observer in the car is 178.5 Hz approximately.
A 15.0kg block is resting on a 2.5 m long board with a coefficient of static friction of 0.45. If one end of the board is slowly raised, at what angle will the block slip?
As the board is raised by an angle θ, the block will be held in place by 3 forces:
• its weight, pointing downward (magnitude w )
• the normal force of the board pushing up on the block, pointing in the direction perpendicular to the board (mag. n)
• static friction, pointing in the direction parallel to the board, opposite the direction the block would slip (mag. f )
Decompose the vectors into components that are parallel and perpendicular to the board (taking the direction of n to be the positive direction perpendicular to the board, and the direction of f to be the negative directoin parallel to it), so that by Newton's second law, we have
• net parallel force:
∑ F = w (//) + f
∑ F = m g sin(θ) - µ n = 0
where µ = 0.45 is the coefficient of static friction, g = 9.80 m/s² is the mag. of the acceleration due to gravity, and m = 15.0 kg is the mass of the block.
• net perpendicular force:
∑ F = n + w (⟂)
∑ F = n - m g cos(θ) = 0
Solve for n in the equation for net perpendicular force:
n = m g cos(θ)
Substitute this into the equation for net parallel force:
m g sin(θ) - 0.45 m g cos(θ) = 0
Solve for θ :
sin(θ) - 0.45 cos(θ) = 0
sin(θ) = 0.45 cos(θ)
tan(θ) = 0.45
θ = tan⁻¹(0.45)
θ ≈ 24.2°
So the maximum angle the board can be lifted before the block starts to slide is about 24.2°, since the coefficient of static friction µ is such that
f = µ n
where f is the maximum magnitude of the static friction force.
Neither past failures nor past successes predict future outcomes, yet we often act on
the basis of
O distorted feedback
O obsolete information
O social expectations
O perfectionism
In most cases, the actions of people could be based on distorted feedback.
How do we see ourselves?We know that self perception and self concept is very important. In psychology, it is often very vital to deal with how a person sees himself as this could be the catalyst of the actions of the person. Let us also recall that people do not often act in isolation of the past. This is why some people are said to be the prisoners of the past. They can not just let go of their past failings and mistakes This could have a very bad impact on then future endeavors of such a person.
Let us put this in the context of our discussion. It is common perception that the past of a person could determine the current or future performances of a person. This is common in recruitment exercises.
This implies that when people tend to act, they tend to act based on distorted feedback.
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On a displacement-time graph, what does a linear slope indicate?
A Velocity is changing.
B Velocity is fixed.
C The car is stationary.
D The car is moving forward.
Answer:
B
Explanation:
The slope (change in position over the change in time) represents the speed, or velocity. If the slope is linear, then that means that the velocity is not changing. It is like a constant rate. If you had a curvy line, then the change in position over change in time would also be changing, i.e. the velocity is changing.
An object travels a distance of 350 km at a rate of 25 m/s. What is the
time it takes to do that?
Answer:
t = 1400 s
Explanation:
Given that,
Distance covered, d = 350 km = 350000 m
Speed of the object, v = 25 m/s
We need to find the time it takes to do that. Let the time is t. The formula for the speed of an object is given by :
v = d/t
i.e.
[tex]t=\dfrac{d}{v}[/tex]
Putting all the values,
[tex]t=\dfrac{350000}{25}\\\\=1400\ s[/tex]
So, the time taken by it is 1400 seconds.
Exercising helps reduce?
Answer:
stress,depression and anxiety by improving self esteem.
Mark takes a 45 minute bike ride through the canyon a total of 4 kilometers what is his speed
Answer:
5.33 km /hr
Explanation:
45 minutes is 3/4 or .75 hr
4 km / .75 hr = 5 1/3 or 5.33 km/hr
Newton's Law of Universal Gravitation states that every object in the universe
Answer: Newton's law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Explanation:
how much work is produced when a 350N object is used to move a car 5 m?
Answer:w= 1,750 J
Explanation: w=f x d
w=350 N x 5 m
w= 1,750 J
(pretty sure that’s right)
The work produced by the object to move the car is of 1750 J.
Given data:
The magnitude of force applied on the object is, F = 350 N.
The distance moved by the car is, s = 5 m.
When some magnitude of force is applied on any object to displace it, then the output of the applied force is known as work done. The mathematical expression for the work done is given as,
[tex]W = F \times s[/tex]
Solving as,
[tex]W = 350 \times 5\\\\W = 1750 \;\rm J[/tex]
Thus, we can conclude that the work produced by the object to move the car is of 1750 J.
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A woman walks 5 meters due east in 12 seconds and then back 2 meters in 7 seconds due west. Determine the person’s velocities for the 5 meters, the 2 meters and the person’s average velocity for the whole walk.
Answer:
Due east - 0.42mps
Due west - 0.29mps
Explanation:
So for the 5 meters 12s
and 2 meters 7s
for the first one we will do 12/5 = 2.4
for the second one 7/2 = 3.5
that is the amount of seconds per meter but we want meters per seconds so
5/12 = 0.42mps
2/7 = 0.29mps
Question 12 of 20
To produce a magnetic field, what does an electromagnet require?
A. A solenoid with no current flowing through it
B. A current flowing through a coil of wire
C. A core made from a magnetic material
D. A copper core
Answer:
B a current flowing through a coil of wire :)
Explanation:
When a current of 2.0A flows in the 100-turn primary of an ideal transformer, this causes 14 A to flow in the secondary. How many turns are in the secondary?A) 700B) 356C) 114D) 14E) 4
Answer: The correct option is D) 14
Explanation:
A transformer is a device used for stepping- up or stepping- down an alternating voltage. It has both primary and secondary windings. Energy is usually supplied through the primary coil and delivered through the secondary coil in a transformer. Using the equation:
Ns= lp
Np= Is
Where Ns--> number of turns in secondary coil
Np--> number of turns in primary coil
Is--> current flow in secondary coil
Ip--> current flow in primary coil.
Therefore Ns= Np Ip/Is
Substituting from the question
Ns= 100×2/14
Ns= 200/14
Ns = 14.28 which is approximately 14 turns in the secondary coil.
What kinds of forces can act on an object
A copper block of mass 0.75 g is removed from a furnace and quickly transferred into a glass beaker of mass 300.0 g containing 200.0 g of water. The temperature of the water rises from 12.0 °C to 27.0 °C. What was the temperature of the furnace?
The temperature of the furnace is 585-degree Celcius.
An expression for hotness or coolness on any scale, including Fahrenheit and Celsius, is called a temperature. Heat energy will logically go from a hotter (body with a higher temperature) to a colder (body with a lower temperature) according to temperature (one at a lower temperature).
Food, beverages, agriculture, and medical care—for both people and animals—all depend heavily on temperature. Temperature also frequently affects our general health in a number of ways. In facilities used for medical cold storage, maintaining optimum temperatures is crucial. The Celsius and Kelvin scales are used in chemistry to express temperature. The Celsius temperature multiplied by 273.15 is the temperature on the Kelvin scale. Absolute zero, denoted by the number 0 K, is the lowest temperature that is conceivable.
instead of 0.75 g, I assume 75 g.
c, water = 4.18 j/g°C
c, glass = 0.84 j/g°C
c, copper = 0.39 j/g°C
Q,given = Q,taken
mcΔt(copper) = mcΔt(glass) + mcΔt(water)
75*0.39*(t–27) = 300*0.84*(27–12) + 200*4.18*(27–12)
t = 585°C
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In a hydraulic garage lift, the smallpiston has a radius of 5.0 cm and the large piston has a radius of15 cm. What force must be applied on the small piston in order tolift a car weighing 20,000 N on the large piston?
a. 6.7 ×103 N
b. 5.0 ×103 N
c. 2.9 ×103 N
d. 2.2 ×103 N
Answer: Option d) 2.2 × 10³ N is the correct answer
Explanation:
Given that;
radius of A₁ = 5.0
large piston has a radius of A₀ = 15 cm
Weight F₀ = 20,000 N
Force that must be applied to lift the weight F₁ = ?
Now we know that from Pascal Law
ΔP ⇒ F₁/A₁ = F₀/A₀
F₁ = (F₀/A₀)A₁
where A = πr²
so we substitute
F₁ = (20,000 / π(15²)) × π(5²)
= (20,000 / 706.8583) × 78.5398
= 2222.22 ≈ 2.2 × 10³ N
Therefore Option d) 2.2 × 10³ N is the correct answer.
what is the amount of matter in an object is called?
Answer:
mass
Explanation:
Answer: Mass is the amount of mass an object contains. Mass is measured using a scale. Volume is the amount of space matter takes up.
hope this help!! :) :)
You travel 25 meters east and then travel 48 meters south. What is your total displacement? Draw a picture what is happening.
Answer: 54.12 m
Explanation:
how to microscope help discovering viruses?
Answer: because it makes it bigger so scientists would discover more about viruses
Explanation:
if a man travels 10m north in 4s, stops for 20s, then travels 20 meters east in 15s, what is the man's average velocity for the trip?
Answer:
The average velocity from 1 to 3 seconds is 20 m/s l. X/T = 0 m/1s = zero.
Explanation:
I hope that helped!
A certain atom has only three energy levels. From lowest to highest energy, these levels are denoted n = 1, n = 2, and n = 3. When the atom transitions from the n = 3 level to the n = 2 level, it emits a photon of wavelength 800 nm. When the atom transitions from the n = 2 level to the n = 1 level, it emits a photon of wavelength 200 nm. What is the wavelength of the photon emitted when the atom transitions from the n = 3 level to the n = 1 level?A. 1000 nm
B. 600 nm
C. 500 nm
D. 160 nm
Answer:
D. 160 nm
Explanation:
The energy released from n = 3 to n = 1 must be equal to the sum of energies released from n = 3 to n = 2 and from n = 2 to n = 1. Therefore,
Energy of Photon from 3 to 1 = Energy of Photon from 3 to 2 + Energy of Photon from 2 to 1
[tex]\frac{hc}{\lambda} = \frac{hc}{\lambda_{1}} + \frac{hc}{\lambda_{2}}\\\\\frac{1}{\lambda} = \frac{1}{\lambda_{1}} + \frac{1}{\lambda_{2}}[/tex]
where,
λ = wavelength of photon released from 3 to 1 = ?
λ₁ = wavelength of photon released from 3 to 2 = 800 nm
λ₂ = wavelength of photon released from 2 to 1 = 200 nm
Therefore,
[tex]\frac{1}{\lambda} = \frac{1}{800\ nm} + \frac{1}{200\ nm}\\\\\frac{1}{\lambda} = 0.00625 nm^{-1}\\\\\lambda = \frac{1}{0.00625 nm^{-1}}\\\\\lambda = 160 nm[/tex]
Therefore, the correct option is:
D. 160 nm
What is the mass of a pet cat that weighs 75N?
Answer:
7.64787 kilograms
Explanation:
75 Newton = 7.64787 Kilograms
hope this helps
pls mark brainliest :D
Answer:
Explanation:
sdfgbaewtfhsertfxzdfhaethsdhdsgfhds
the question is in a picture
Answer:
same for all objects
Explanation:
earth pulls every object by same force of gravity
When a falling meteoroid is at a distance above the Earth's surface of 3.40 times the Earth's radius, what is its acceleration due to the Earth's gravitation
Answer:
g = 0.85 m[tex]s^{-2}[/tex]
Explanation:
g = [tex]\frac{GM}{h^{2} }[/tex]
were; g is the acceleration due to Earth's gravity, G is Newton's gravitation constant (6.674 x [tex]10^{-11}[/tex] N[tex]m^{2}[/tex][tex]kg^{-2}[/tex]), M is the mass of the earth (5.972 x [tex]10^{24}[/tex] kg), and h is the distance of meteoroid to the earth.
h = 3.40 x R
= 3.40 x 6371 km
h = 21661.4 km
= 21661400 m
Thus,
g = [tex]\frac{6.674*10^{-11}*5.972*10^{24} }{(21661400)^{2} }[/tex]
= [tex]\frac{3.9857 *10^{14} }{4.6922*10^{14} }[/tex]
= 0.84944
g = 0.85 m[tex]s^{-2}[/tex]
The acceleration due to the Earth's gravitation is 0.85 m[tex]s^{-2}[/tex].
Which part of an object's rate of change best defines acceleration?
force
speed
oposition
velocity
Answer:
velocity
Explanation:
acceleration is defined as the rate of change of velocity
If the IMA of a machine Is 3 and the resistance arm Is 6 meters, then the effort arm is? 2 meters, 3 meters, 9 meters, 18 meters.
Answer:
18 newtons
Explanation: I'm taking that class
for two vectors A and B, if A×B =6i+2j+5k, A.B=-13, A+B=-2i+j+2k and magnitude of vector A is 3. find the two vectors A anf B
Two vectors are parallel when the angle between them is either 0° (the vectors point in the same direction) or 180° (the vectors point in opposite directions).
What is vectors ?In both mathematics and physics, the term "vector" is used informally to describe certain quantities (also known as "scalars") that cannot be described by a single number or by the constituent parts of some vector spaces.
Historically, vectors were introduced in geometry and physics (usually in mechanics) for things like displacements, forces, and velocity that have both a magnitude and a direction. Similar to how lengths, masses, and time are represented by real numbers, these quantities can be thought of as geometric vectors.
Tuples, which are finite sequences of numbers with a definite length, are also referred to as vectors in some settings.
Tuples and geometric vectors may both be added to and scaled, and the idea of a vector space is a result of these vector operations.
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parar 7. Keira starts at position x = 23 m along a coordinate axis. She then undergoes a displacement of -45 m. What is her final position? nood A coordinate
Answer: x=-22
Explanation:
f=final position
-45=f-23
-45+23=f
f=-22
x=-22
How does light move?
Answer:
Light travels as a wave. But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuum—a completely airless space. It speeds through the vacuum of space at 186,400 miles (300,000 km) per second.
Explanation:
Hope this helps :))
Jonas has a 10.0 kg box, which he places on a scale inside an elevator. When the
elevator begins to move, the scale shows that the box weighs 83.4 N. What is the
magnitude and direction of the elevator's acceleration?
Answer:
a = - 1.47 [m/s²], descending or going down
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 10 [kg]
a = acceleration [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.
[tex]-m*g + N = m*a\\[/tex]
where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force measured by the scale = 83.4 [N]
Now replacing:
[tex]-(10*9.81)+83.4=10*a\\-14.7=10*a\\a=-1.47[m/s^{2} ][/tex]
The acceleration has a negative sign, this means that the elevator is descending at that very moment.