A car travels 60 km in the first 2 hours and 68 km in the next 2 hours. what is the cars average speed ?
A soccer ball with a mass of 0.427 kg approaches a player horizontally with a speed of 16.0 m/s. The player kicks the ball with her foot, which causes the ball to move in the opposite direction with a speed of 21.7 m/s.
Required:
a. What magnitude of impulse (in kg · m/s) is delivered to the ball by the player?
b. What is the direction of the impulse delivered to the ball by the player?
c. If the player's foot is in contact with the ball for 0.0600 s, what is the magnitude of the average force (in N) exerted on the player's foot by the ball?
Explanation:
Given that,
Mass of a soccer ball, m = 0.427 kg
Initial speed, u = 16 m/s
Final speed, v = -21.7 m/s (negative as it is in opposite direction)
(a) Impulse = change in momentum
J = 0.427 × (-21.7 -16)
J = -16.097 kg-m/s
(b) Impulse delivered to the ball by the player is in opposite direction.
(c) Time of contant, t = 0.0600 s
Average force,
J = force×time
[tex]F=\dfrac{J}{t}\\\\F=\dfrac{16.097}{0.0600 }\\\\=268.28\ N[/tex]
Hence, this is the required solution.
What is the net force on a truck if the force of friction is 31 N and the force of the engine is 79 N?
48 N backword
79 N forward
48 N forward
110 N forward
Answer:
Fr = 48 [N] forward.
Explanation:
Suppose the movement is on the X axis, in this way we have the force of the engine that produces the movement to the right, while the force produced by the brake causes the vehicle to decrease its speed in this way the sign must be negative.
∑F = Fr
[tex]F_{engine}-F_{brake} =F_{r}\\F_{r}=79-31\\F_{r}=48[N][/tex]
The movement remains forward, since the force produced by the movement is greater than the braking force.
Older televisions display a picture using a device called a cathode ray tube, where electrons are emitted at high speed and collide with a phosphorescent surface, causing light to be emitted. The paths of the electrons are altered by magnetic fields. Consider one such electron that is emitted with an initial velocity of 1.85 107 m/s in the horizontal direction when magnetic forces deflect the electron with a vertically upward acceleration of 5.45 1015 m/s2. The phosphorescent screen is a horizontal distance of 5.6 cm away from the point where the electron is emitted. (a) How much time does the electron take to travel from the emission point to the screen? (b) How far does the electron travel vertically before it hits the screen?
Answer:
a) t = 3.027 10⁻⁹ s , b) y = 2.25 10⁻² m
Explanation:
We can solve this problem using the kinematic relations
a) as on the x-axis there is no relationship
vₓ = x / t
t = x / vₓ
We reduce the magnitudes to the SI system
x = 5.6 cm (1m / 100 vm) = 0.056 m
we calculate
t = 0.056 / 1.85 10⁷
t = 3.027 10⁻⁹ s
b) the time is the same for the two movements, on the y axis
y = v₀t + ½ a t²
as the beam leaves horizontal there is no initial vertical velocity
y = ½ a t²
let's calculate
y = ½ 5.45 10¹⁵ (3.027 10⁻⁹)²
y = 2.25 10⁻² m
12. Why do you think afternoons are much warmer than the mornings or evenings?
Answer:
Afternoons are much warmer than the mornings or evenings is explained below in complete detail.
Explanation:
Because in the afternoon the sun is on the head and the beams of sunshine arrive straight to the earth so we exhibit warmer and in daylight and evening the sun is sparse to the earth so we observe colder than an afternoon. However, in the evening, when the sun is weak, I don't sense or experienced loads of heat and sunburn on body parts that are viewing the sun directly.
PLEASE HELP!!
To conclude, how would you explain
electromagnetic induction to a 5 year old?
words to include: magnets, electricity, and
change.
Answer:
fgdyauqushxhxxgxggxgxgxgsgsysysy
sysydyydydysysysysyxhxyt56fys7w727ueudu
A tennis ball is hit with an initial velocity of 15 m/s at an angle of
40°. What is the horizontal distance of the ball after 2 seconds?
(round to the nearest meter)
Answer:
Horizontal acceleration is 0 in a projectile motion
Explanation:
first we have to find the horizontal velocity
15cos40 = 11.49ms^-1
and then use the following equation to find the distance
[tex]s = ut + \frac{1}{2} a {t}^{2} \\ s = 11.49 \times 2 \\s = 22.98m[/tex]
Given:
Initial velocity = 15 m/sAngle = 40°According to the question,
→ [tex]15 \ Cos 40^{\circ} = 11.49 \ m/s^{-1}[/tex]
By using the relation, we get
→ [tex]s = ut +\frac{1}{2}at^2[/tex]
By substituting the values, we get
[tex]= 11.49\times 2[/tex]
[tex]= 22.98 \ m[/tex]
Thus the response above is correct.
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A thin-walled vessel of volume V contains N particles which slowly leak out of a small hole of area A. No particles enter the volume through the hole. Find the time required for the number of particles to decrease to N/2. Express your answer in terms of A, V, and v.
Answer:
[tex]\frac{V}{2av}[/tex]
Explanation:
From the question we are told that
Volume V
Contains N particles
Leaks from a small hole of area A
Generally the equation for Flow rate is given as
Volume Flow Rate [tex]V_r = A * v[/tex]
Mathematically we find the time taken to flow half way which is given by
[tex]\frac{(V/2)}{A*v}[/tex]
Therefore the time taken is
[tex]\frac{V}{2av}[/tex]
The y-component of the force F which a person exerts on the handle of the box wrench is known to be 70 lb. Determine the x-component and the magnitude of F.
Answer:
Fx = 121.24lb
F = 140lb
Explanation:
Since we are not given the angles subtended by the force, we can assume it to be 30 degrees.
The y component of the force expressed by the formula:
Fy = Fsintheta
Given the y-component of the force F to bee 70lb
70lb = Fsintheta
Get magnitude of the force
F = 70/sin theta
F = 70/sin 30
F = 70/0.5
F = 140lb
Get the x-component of the force
Fx = Fcos theta
Fx = 140cos 30
Fx = 140(0.8660)
Fx = 1,212.4lb
Hence the x-component of the force sis 121.24lb
Note that the angle used was assumed. Other values can as well be used
The specific heat of aluminum is 0.90 J/gC . How much heat is given off when 25 grams of aluminum is cooled from 55 C to 25 C?
Answer:
Q = 675 [J]
Explanation:
We can calculate the amount of heat transfer by means of the following expression that includes the mass and temperature change in a body as a function of the specific heat.
[tex]Q=m*C_{p}*(T_{initial}-T_{final})[/tex]
where:
m = mass = 25 [gr]
Cp = specific heat = 0.9 [J/g*°C]
Tinitial = 55 [°C]
Tfinal = 25 [°C]
[tex]Q=25*0.9*(55-25)\\Q=675 [J][/tex]
If a person throws a wiffle ball and a tennis ball with the same speed, which object would travel with more kinetic
energy? Justify your selection
Answer:
The tennis ball will have more kinetic energy
Explanation:
It will have more kinetic energy because the tennis ball is more heavier than a wiffle ball. Furthermore, objects that are heavy will have more kinetic energy than objects that are light. Therefore, the tennis ball is the correct answer.
The tennis ball will have more kinetic energy as compared to the wiffle ball, because tennis ball is more heavier.
The energy possessed by any object due to virtue of its motion is known as kinetic energy. The standard expression for the kinetic energy is given as,
[tex]KE = \dfrac{1}{2}mv^{2}[/tex]
Here,
m is the mass of balls.
v is the speed of balls.
Clearly the kinetic energy of any object is dependent on the mass and velocity. So with same velocity, the heavier object will have more kinetic energy. Since, the tennis ball is more heavier as compared to the wiffle ball, therefore kinetic energy of tennis ball will be more.
Thus, we can conclude that the tennis ball will have more kinetic energy as compared to the wiffle ball, because tennis ball is more heavier.
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An alpha particle has twice the charge of a beta particle. Why does the former deflect less than the latter when passing between electrically charged plates, assuming they both have the same speed?
A steel wire in a piano has a length of 0.540 m and a mass of 4.800 ✕ 10−3 kg. To what tension must this wire be stretched so that the fundamental vibration corresponds to middle C (fC = 261.6 Hz on the chromatic musical scale)?
Answer:
T = 708.81 N
Explanation:
Given that,
Length of a steel wire in a piano, l =0.54 m
Mass, [tex]m=4.8\times 10^{-3}\ kg[/tex]
We need to find the tension must this wire be stretched so that the fundamental vibration corresponds to middle C, fc = 261.6 Hz
The equation for fundamental frequency is given by :
[tex]f=\dfrac{1}{2l}\times \sqrt{\dfrac{T}{\mu}} \\\\f=\dfrac{1}{2l}\times \sqrt{\dfrac{T}{\dfrac{m}{l}}} \\\\261.6=\dfrac{1}{2\times 0.54}\times \sqrt{\dfrac{T}{\dfrac{4.8\times 10^{-3}}{0.54}}} \\\\261.6\times 2\times 0.54=\sqrt{\dfrac{T}{\dfrac{4.8\times 10^{-3}}{0.54}}}\\\\282.528=\sqrt{\dfrac{T}{0.00888}} \\\\(282.528)^2=\dfrac{T}{0.00888}\\\\T=708.81\ N[/tex]
So, the required tension in the wire is 708.81 N.
Gravitational Potential Energy: You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy of you and your friend, after you both reach the top.
Answer:
Gravitational Potential Energy of both will be equal
Explanation:
The gravitational potential energy is given by the following formula:
[tex]P.E = mgh[/tex]
where,
P.E = Gravitational Potential Energy
m = mass of object
g = acceleration due to gravity
h = height of object
Therefore, the gravitational potential energy of an object depends only upon the height of the object and its mass.
Since, both masses and the heights achieved by both people is equal. Therefore, their gravitational potential energies will also be equal
In a test run, a certain car accelerates uniformly from zero to 20.4 m/s in 2.60 s.
Required:
a. What is the magnitude of the cars acceleration?
b. How long does it take the car to change speed from 10.0 m/s to 20 m/s.
c. Will doubling the time always double the change in speed? why?
Answer:
(a) The acceleration is 7.85 m/s²
(b) It takes the car to change speed from 10.0 m / s to 20 m / s in a time of 1.27 seconds.
(c) Doubling the time will double the change in velocity if the acceleration is kept constant.
Explanation:
(a) Acceleration is the physical quantity that measures the rate of change of velocity with time. That is, acceleration relates changes in speed with the time in which they occur, that is, it measures how fast the changes in speed are.
The average acceleration is calculated using the following expression:
[tex]a=\frac{vf-vi}{t}[/tex]
where a is the acceleration, vf is the final velocity, vi is the initial velocity and t is the time.
In this case:
vf= 20.4 m/svi=0 m/st= 2.60 sReplacing:
[tex]a=\frac{20.4 \frac{m}{s} - 0\frac{m}{s} }{2.60 s}[/tex]
a= 7.85 m/s²
The acceleration is 7.85 m/s²
(b) In this case you know:
a= 7.85 m/s²vf= 20 m/svi= 10 m/sReplacing:
[tex]7.85 \frac{m}{s^{2} } =\frac{20 \frac{m}{s} - 10\frac{m}{s} }{t}[/tex]
and solving you get:
[tex]t=\frac{20 \frac{m}{s} - 10\frac{m}{s} }{7.85 \frac{m}{s^{2} } }[/tex]
t=1.27 s
It takes the car to change speed from 10.0 m / s to 20 m / s in a time of 1.27 seconds.
(c) Being:
[tex]a=\frac{vf-vi}{t}[/tex]
Then:
a*t= vf - vi
vf - vi represents the change in velocity. You can see that, if a (acceleration) is constant, then (vf - vi) is directly proportional to the time t: therefore, if t doubles, the change in velocity doubles as well.
In other words, doubling the time will double the change in velocity if the acceleration is kept constant.
Which of the following is not a metric base unit? *
Meter
Liter
Inch
Gram
Answer:
Liter
Explanation:
How does thermal energy change matter?
Answer:
maxed out
Explanation:
which items are matter?
Answer:
which items are matter?
battery , mobile phone
In schematic diagrams, currents are indicated using arrows. What do the arrows indicate? a) the direction of motion of the electrons b) the direction of the current vector c) the direction of motion of the charge carriers d) the direction that positive charge carriers would move e) nothing; they are just a convenient drawing tool
Answer:
D
Explanation:
The direction that positive charge would move
. Momentum is ____________ proportional to an objects mass and its velocity, meaning that if either the mass or the velocity increases, the momentum will _______________.
Answer:
1) directly
2) increase or double
Explanation:
Momentum is directly proportional to an objects mass and its velocity, meaning that if either the mass or the velocity increases, the momentum will double/increase.
A 3.1 kg block initially at rest is pulled to the right along a horizontal frictionless surface by a constant horizontal force of 16.6 N. Find the speed after it has moved 3.8m.
We know, acceleration is given by :
a = F/m
a = 16.6/3.1 m/s²
a = 5.35 m/s²
Now, we need to find the speed after it has moved 3.8 m.
By equation of motion :
[tex]v^2 -u^2 = 2as\\\\v=\sqrt{2as}\\\\v = \sqrt{2\times 5.35 \times 3.8 }\ m/s\\\\v = 6.38\ m/s[/tex]
Therefore, the speed after it has moved 3.8 m is 6.38 m/s.
Q1: An object is in a uniform circular motion. Which of the following statements must be
true?
Answer:
it has constant angular velocity
Explanation:
an object moving in a uniform circular motion moves with constant angular velocity about a point
Mental processes refers to
overt actions and reactions.
only animal behavior.
internal, covert processes.
outward behavior.
To what temperature will 9400J of heat raise 3.5kg of water that is initially at 18.0?C? The specific heat of water is 4186 J/kg?C?.
Answer:
[tex]T_f=18.641^{\circ} C[/tex]
Explanation:
Given that,
Heat raised, Q = 9400 J
Mass, m = 3.5 kg
Initial temperature of water, [tex]T_i=18^{\circ} C[/tex]
The specific heat of water, [tex]c=4186\ J/kg^{\circ} C[/tex]
We need to find the final temperature of water. The heat required to raise the temperature is given by :
[tex]Q=mc\Delta T\\\\Q=mc(T_f-T_i)\\\\\dfrac{Q}{mc}=(T_f-T_i)\\\\T_f=\dfrac{Q}{mc}+T_i\\\\T_f=\dfrac{9400}{3.5\times 4186}+18\\\\=18.641^{\circ} C[/tex]
So, the final temperature is [tex]18.641^{\circ} C[/tex].
BERE
Which describes the positions on a horizontal number line?
0
O All points to the left of one are positive.
O All points to the right of one are positive.
O All points to the left of zero are negative.
O All points to the right of zero are negative.
Mark this and return
Save and Exit
Next
Submit
Answer:
All points to the left of zero are negative
Explanation:
Answer:
C
Explanation:
on edge
A boy takes his dog for a walk. The dog pulls with 30N of force to the right and the boy pulls backward with 18 N of force.
Net Force = (your answer)
Body Diagram or Explanation = (your answer)
Answer:
Answer is in photo
Explanation:
PLEASE ANSWER ASAP BEFORE MY TEACHER AND MY MOM KILLES ME PLEASE ASAP
The first person with the right answer gets to be a brainlest
In the attachment there is a density column where there is colour
Question: tell me why is the red at the bottom of the density column if it is the least dense
The most dense thing inside the column is the little star. It's pink, and it's resting on the bottom of the cylinder.
The red part under the star is the solid base that the cylinder is standing in. It's probably wood or plastic, it's not free to move, and it's not involved in the experiment.
Answer: That is not meant to be red, it‘s the bottom of the beaker. The star is at the very bottom of the beaker. it’s just the base of the beaker.
Kelli drew a diagram to compare cast and imprint fossils. Which label belongs in the area marked Y? Involves minerals replacing remains of organism Takes millions of years to form Gives evidence of organism's activity Involves mold filling with minerals and sediment
Answer:
D. Involves mold filling with minerals and sediment
Explanation:
The given part y is in the inter region of the circle labelled cast and imprints. Thus, it belongs to both. Cast fossils are a type of imprint fossils which are filled with minerals from sediments and hardens to form the fossils. Thus, option d is correct.
What are fossils?Fossils are decomposed plants or animals or their imprints indicating their actions such as footprints, shells etc. There are broadly two types of fossils namely body fossils and trace fossils.
Body fossils are decomposed body parts of animals or plants such as bones, tree branches, skull etc. Trace fossils are imprints of the animals or plants such as footprints, shells, caves, skin etc.
Imprint fossils are the impression of any activities or behaviour of living things. shell, leaf, caves etc are imprint fossils. Cast fossils are formed by filling of imprint fossils with minerals reached from water and sediments and hardened to fossils. Therefore, the given area is cast fossil and option d is correct.
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Why is it easier to swim in sea than in a pond or river?
Answer:
Since sea water contains alot of salt the density of the sea water is higher as to the river water . So it makes it easier to swim in sea water
How many hours will it take to fill a cubic vat of 15.7 ft edge length with a liquid that has a density of 1.31 g/mL and is spilling at a rate of 2.30 kg/s
Answer:
240 s or 4 minutes.
Explanation:
Given that
Volume of the cubic vat is 15.7³ = 3869.893 ft³
Density of the liquid is 1.31 g/mL
For easier calculations, we need to convert the density from g/mL to ft³
conversion factors shall be CUBED in order to do it!
We know that
1 inch = 2.54 cm, and
1 foot = 12 in
This means that
1.31 g/cm³ * 2.54³ cm³/in³ * 12³ in³/ft³
= 37095.069 g/ft³
Lastly,
We use this conversion method
1 second/ 2300 grams * 37095.069 g/ft = 16.13 ft³/s
Bringing down the volume of the cube, we use it to divide, and thus
3869.893 / 16.13 = 240 seconds
240 seconds = 4 minutes