FINAL EXAM Flashcards
What is Newton’s 1st Law of motion?
A body at rest remains at rest and a body in motion continues to move at constant velocity along a straight line unless acted upon by an external force.
What is Newton’s 2nd Law of motion?
What is Newton’s 3rd Law of motion?
For every action force on an object there is a reaction force that is equal in magnitude and opposite in direction. Third Law Force Pairs
When the man pushes a refrigerator across a kitchen floor at a constant speed, the force of friction between the refrigerator and the floor is
A. equal and in the opposite direction as the man’s push.
B. equal and in the same direction as the man’s push.
C. less than and in the same direction as the man’s push.
D. more than and in the opposite direction as the man’s push
A. equal and in the opposite direction as the man’s push.
A skydiver has reached terminal velocity—she now falls at a constant speed, so her acceleration is zero. Is there a net force on her? If so, what is the direction?
A. There is a net force directed upward.
B. There is no net force.
C. There is a net force directed downward.
B. There is no net force.
Two people of equal mass on slippery ice are standing still and then push off from each other. Will both move at the same speed in opposite directions?
A. Yes
B. Yes, but only if both push equally.
C. No
A. Yes
You are riding in an elevator that is accelerating upward. Suppose you stand on a scale. The reading on the scale is
A. Greater than your true weight.
B. Equal to your true weight.
C. Less than your true weight.
A. Greater than your true weight
In general, the coefficient of static friction is
A. Smaller than the coefficient of kinetic friction.
B. Equal to the coefficient of kinetic friction.
C. Greater than the coefficient of kinetic friction.
C. Greater than the coefficient of kinetic friction.
The drag force pushes opposite your motion as you ride a bicycle. If you double your speed, what happens to the magnitude of the drag force?
A. The drag force will double
B. The drag force will quadruple.
C. The drag force stays the same.
D. The drag force decreases.
B. The drag force will quadruple.
A box is being pulled to the right at steady speed by a rope that angles upward. In this situation:
A. n is greater than mg
B. n is equal to mg
C. n is less than mg
D. n is equal to 0
C. n is less than mg
A box with a weight of 100 N is at rest. It is then pulled by a 30 N horizontal force.
The coefficient of static and kinetic friction are listed below.
Does the box move?
No
A box is being pulled to the right over a rough surface with tension T, where
T > fk. So the box is speeding up. Suddenly the rope breaks.
What happens? The box
A. Stops immediately.
B. Continues with the speed it had when the rope broke.
C. Continues speeding up for a short while, then slows and stops.
D. Keeps its speed for a short while, then slows and stops.
E. Slows steadily until it stops.
E. Slows steadily until it stops.
A ring, seen from above, is pulled on by three forces. The ring is not moving. How big is the force F?
A. 20 N
B. 10 cos ϴ (in N)
C. 10 sin ϴ (in N)
D. 20 cos ϴ (in N)
E. 20 sin ϴ (in N)
E. 20 sin ϴ (in N)
If you are not wearing a seat belt and the car you are driving hits a fixed barrier, you will hit the steering wheel with some force. This is because
A. The force of the collision has thrown you forward.
B. The steering wheel has been pushed back toward you.
C. You continue moving even after the car has stopped.
C. You continue moving even after the car has stopped.
If you stand on a trampoline, it depresses under your weight. When you stand on a hard stone floor, what happens?
A. The floor does not deform under your weight; it is too stiff.
B. The floor deforms—very slightly—under your weight.
C. The floor deforms a slight amount if you are heavy enough.
B. The floor deforms—very slightly—under your weight.
An elevator, lifted by a cable, is moving upward and slowing. What is the correct free-body diagram?
A car is parked on a hill. What is the correct free-body diagram?
When the man pushes a refrigerator across a kitchen floor at a constant speed, the force of friction between the refrigerator and the floor is
A. equal and in the opposite direction as the man’s push.
B. equal and in the same direction as the man’s push.
C. less than and in the same direction as the man’s push.
D. more than and in the opposite direction as the man’s push
A. equal and in the opposite direction as the man’s push.
Consider a high-speed bus colliding head-on with a flying bug. The force of impact splatters the unfortunate bug over the windshield.
Which is greater, the force on the bug or the force on the bus?
A. Bug
B. Bus
C. Both are the same amount.
C. Both are the same amount.
When you step off a curb, Earth pulls you downward. The reaction to this force is
A. slight air resistance.
B. you pulling Earth upward.
C. there is no reaction to this force.
B. you pulling Earth upward.
Two people of equal mass on slippery ice are standing still and then push off from each other. Will both move at the same speed in opposite directions?
A. Yes
B. Yes, but only if both push equally.
C. No
A. Yes
When a cannon is fired, the accelerations of the cannon and cannonball are different because the:
A. forces don’t occur at the same time.
B. forces, although theoretically the same, in practice are not.
C. masses are different.
D. ratios of force to mass are the same.
C. masses are different.
A skydiver has reached terminal velocity—she now falls at a constant speed, so her acceleration is zero. Is there a net force on her? If so, what is the direction?
A. There is a net force directed upward.
B. There is no net force.
C. There is a net force directed downward.
B. There is no net force.
The acceleration vector of a particle in projectile motion
A. Points along the path of the particle.
B. Points horizontally at all times.
C. Vanishes at the particle’s highest point.
D. Points down at all times.
E. Is zero.
D. Points down at all times.
The acceleration vector of a particle in uniform circular motion
A. Is zero.
B. Points toward the center of the circle.
C. Points outward from the center of the circle.
D. Points tangent to the circle, in the direction of motion.
E. Points tangent to the circle, opposite the direction of motion.
B. Points toward the center of the circle.
A factory conveyor belt rolls at 3 m/s. A mouse sees a piece of cheese directly across the belt and heads straight for the cheese at 4 m/s. What is the mouse’s speed relative to the factory floor?
5 m/s
Consider the two cars movements below.
Both have the same time interval between photos. Which car, A or B, is going slower?
A
How many significant figures does this number have?
0.00673
3
How many significant figures does this number have?
0.9510
4
Which position diagram shows a car slowing down?
Remember, the car positions are taken at equal time intervals.
C
Consider the motion diagram below of a car moving along a straight road. What is the velocity graph that matches the motion of the car?
Consider the motion diagram below of a car moving along a straight road. What is the velocity graph that matches the motion of the car?
The graph below is a velocity versus time for a hockey puck shot into a goal. What position graph matches the velocity graph?
A ball moves to the left and is slowing down. What is the sign of acceleration?
A. Positive
B. Negative
A. Positive
In rotational motion, θ is positive when measured [ ] from the positive x-axis.
counterclockwise (CCW)
In rotational motion, θ is negative when measured [ ] from the positive x-axis.
clockwise (CW)
In rotational motion, which unit represents arc length?
The arc length, s, is the distance that the particle has traveled along its circular path.
Define angular velocity (omega, w)
Angular velocity is the angular displacement through which the particle moves each second
1 mi = ? m
1 mi = 1609 m
In rotational motion, how is 1 revolution measured?
2pi
Torque (τ) is the rotational equivalent of
force.
Torque is in units of
newton-meters, N × m.
[ ] is the line starting at the pivot and extending through the point where force is applied.
Radial Line
A torque causes an angular
acceleration.
The moment of inertia is the rotational equivalent of
mass.
What is Newton’s second law of rotation?
If more than one torque acts on a rigid body about a fixed axis, then the sum of the torques equals the moment of inertia times the angular acceleration
Two conditions for static equilibrium on an extended object:
- The net force on the object must be zero.
- The net torque on the object must be zero.
A car is turning a corner at a constant speed, following a segment of a circle.
What force provides the necessary centripetal acceleration?
A. Gravity
B. Normal Force
C. Static Friction
D. Kinetic Friction
C. Static Friction
A ball at the end of a string is being swung in a horizontal circle. What force is producing the centripetal acceleration of the ball?
Gravity
Air resistance
Normal force
Tension in the string
Tension in the string
A ball at the end of a string is being swung in a horizontal circle.
What is the direction of the net force on the ball?
Tangent to the circle
Toward the center of the circle
Away from the center of the circle
There is no net force
Toward the center of the circle
Astronauts on the International Space Station are weightless because
There’s no gravity in outer space.
The net force on them is zero.
The centrifugal force balances the gravitational force.
g is very small, although not zero.
They are in free fall.
They are in free fall.
A passenger on a carnival ride rides in a car that spins in a horizontal circle as shown below.
At the instant shown, which arrow gives the direction of the net force on one of the riders?
A.
B.
C.
D.
D
If an object is rotating clockwise, this corresponds to a ______ angular velocity.
Positive
Negative
Negative
The fan blade is slowing down. What are the signs of ω and α?
ω is positive and α is positive.
ω is positive and α is negative.
ω is negative and α is positive.
ω is negative and α is negative.
ω is positive and α is zero.
ω is negative and α is positive.
The fan blade is speeding up. What are the signs of w and α?
ω is positive and α is positive.
ω is positive and α is negative.
ω is negative and α is positive.
ω is negative and α is negative.
ω is positive and α is zero.
ω is negative and α is negative
The four forces shown have the same strength. Which force would be most effective in opening the door?
Force F1
Force F2
Force F3
Force F4
Force F1
A net torque applied to an object causes
A linear acceleration of the object.
The object to rotate at a constant rate.
The angular velocity of the object to change.
The moment of inertia of the object to change.
The angular velocity of the object to change.
Two coins rotate on a turntable. Coin B is twice as far from the axis as coin A.
The angular velocity of A is twice that of B
The angular velocity of A equals that of B
The angular velocity of A is half that of B
The angular velocity of A equals that of B
Two coins rotate on a turntable. Coin B is twice as far from the axis as coin A.
Which coin has the larger linear (tangential) velocity?
A
B
They have the same linear velocity
B
Two spheres have the same radius and equal masses. One is made of solid aluminum and the other is made of a hollow shell of gold.
Which sphere has the bigger moment of inertia about an axis through its center?
Solid Aluminum Sphere
Hollow Gold Sphere
They have the same moment of inertia
Hollow Gold Sphere
An object is in equilibrium if
Fnet = 0
τnet = 0
Either A or B
Both A and B
Both A and B
The scale is positioned half-way between the mass and the pivot point. What does the scale read?
500 N
1000 N
2000 N
4000 N
2000 N
An object will be stable if
Its center of gravity is below its highest point.
Its center of gravity lies over its base of support.
Its center of gravity lies outside its base of support.
The height of its center of gravity is less than 1/2 its total height.
Its center of gravity lies over its base of support.
The restoring force of three springs is measured as they are stretched. Which spring has the largest spring constant?
A
B
C
A
A very rigid material—one that stretches or compresses only slightly under large forces—has a large value of
Tensile strength.
Elastic limit.
Density.
Young’s modulus.
Young’s modulus.
A person stands on a very light rigid board that rests on a bathroom scale at each end. The left scale reads 35 lbs and the right scale reads 105 lbs. What is the weight of the person?
70 lbs
105 lbs
140 lbs
185 lbs
140 lbs
A light plastic cart and a heavy steel cart are both pushed with the same force for 1.0 s, starting from rest. After the force is removed, the momentum of the light plastic cart is ________ that of the heavy steel cart.
Greater than
Equal to
Less than
Equal to
A 10 kg cart moves to the left with a velocity of 2 m/s, hits a wall and then moves back toward the right with a velocity of 1 m/s. What is the change of momentum Δp that the cart experiences?
–20 kg m/s
–10 kg m/s
0 kg m/s
10 kg m/s
30 kg m/s
30 kg m/s
Consider a dish falling to the ground.
What can you say about the change in momentum when it falls on a carpet verses a hard floor?
The change in momentum is less on the carpet
The change in momentum is more on the carpet
The change in momentum is the same for both carpet and floor
The change in momentum is the same for both carpet and floor
The 1-kg box is sliding along a frictionless surface. It collides with and sticks to the 2-kg box. Afterward, the speed of the two boxes is
0 m/s
1 m/s
2 m/s
3 m/s
1 m/s
The two boxes are sliding along a frictionless surface. They collide and stick together. Afterward, the velocity of the two boxes is
2 m/s to the left
1 m/s to the left
0 m/s, at rest
1 m/s to the right
2 m/s to the right
0 m/s, at rest
The two boxes are on a frictionless surface. They were sitting together at rest, but an explosion between them has just pushed them apart. The 1 kg box moves to the left at 4 m/s.
How fast is the 2-kg box going?
1 m/s
2 m/s
4 m/s
8 m/s
2 m/s
A mosquito and a truck have a head-on collision. Splat! Which has a larger change of momentum?
The mosquito
The truck
They have the same change of momentum.
They have the same change of momentum.
You awake in the night to find that your living room is on fire. Your one chance to save yourself is to throw something that will hit the back of your bedroom door and close it, giving you a few seconds to escape out the window. You happen to have both a sticky ball of clay and a super-bouncy Superball next to your bed, both the same size and same mass. You’ve only time to throw one. Which will it be?
Throw the Superball.
Throw the ball of clay.
It doesn’t matter. Throw either.
Throw the Superball.
An object’s angular momentum is proportional to its
Mass.
Moment of inertia.
Kinetic energy.
Linear momentum.
Moment of inertia.
A child is on a playground swing, motionless at the highest point of his arc. What energy transformation takes place as he swings back down to the lowest point of his motion?
K ⇒ Ug
Ug ⇒ K
Eth ⇒ K
Ug ⇒ Eth
K ⇒ Eth
Ug ⇒ K
Both skiers push off with a Force of 500 N. Which skier will be faster at the bottom of the hill?
Red Skier
Blue Skier
They will have the same speed
Blue Skier
A tow rope pulls a skier up the slope at constant speed. What energy transfer (or transfers) is/are taking place?
W ⇒ Ug
W ⇒ K
W ⇒ Eth
Both A and B.
Both A and C.
Both A and C.
Starting from rest, two identical marbles each roll down a frictionless hill both of which are at the same height. One hill is more steep than the other as shown below. Which marble is going faster at the bottom?
The marble going down the steeper hill is faster.
The marble going down the less steep hill is faster.
Both marbles have the same speed at the bottom.
Both marbles have the same speed at the bottom.
c A hockey puck sliding on smooth ice at 4 m/s comes to a 1-m-high hill. Will it make it to the top of the hill?
Yes.
No.
No.
Three balls are thrown from a cliff with the same speed but at different angles. Which ball has the greatest speed just before it hits the ground?
Ball A.
Ball B.
Ball C.
All balls have the same speed.
All balls have the same speed.
Four students run up the stairs in the time shown. Which student has the largest power output?
A.
B.
C.
D.
B.
Each of the 1.0 kg boxes starts at rest and is then pulled for 2.0 m across a level, frictionless floor by a rope with the noted force and angle. Which box has the highest final speed?
B.
If you raise an object to a greater height, you are increasing
Kinetic energy.
Heat.
Potential energy.
Chemical energy.
Thermal energy.
Potential energy.
If you hold a heavy weight over your head, the work you do
Is greater than zero.
Is equal to zero.
Is less than zero.
Is converted into chemical energy.
Is converted into potential energy.
Is equal to zero.
Which of the following is an energy transfer?
Kinetic energy
Work
Potential energy
Chemical energy
Thermal energy
Work
A person throws a javelin into the air. As she propels it forward from rest, she does 270 J of work on it. At its highest point, its gravitational potential energy has increased by 70 J. What is the javelin’s kinetic energy at this point?
270 J
340 J
200 J
–200 J
–340 J
200 J
The following pairs of temperatures represent the temperatures of hot and cold reservoirs for heat engines. Which heat engine has the highest possible efficiency?
300°C, 30°C
250°C, 30°C
200°C, 20°C
100°C, 10°C
90°C, 0°C
300°C, 30°C
The efficiency of this heat engine is
1.00
0.60
0.50
0.40
0.20
0.40
A large –20°C ice cube is dropped into a super-insulated container holding a small amount of 5°C water, then the container is sealed. Ten minutes later, the temperature of the ice (and any water that has melted from the ice) will be warmer than –20°C. This is a consequence of
The first law of thermodynamics.
The second law of thermodynamics.
The third law of thermodynamics.
Both the first and the second laws.
The second law of thermodynamics.
When you walk at a constant speed on level ground, what energy transformation is taking place?
Echem → Ug
Ug → Eth
Echem → K
Echem → Eth
K → Eth
Echem → Eth
A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J.
What is the efficiency of this process?
100%
85%
70%
35%
30%
30%
Define isolated system
An isolated system is a system with no net external force acting on it, leaving the momentum unchanged.
p2 = p3 > p1
B. II
A heavy lead block and a light aluminum block of equal sizes are both submerged in water. Upon which is the buoyant force greater?
On the lead block
On the aluminum block
They both experience the same buoyant force.
They both experience the same buoyant force.
When taking a patient’s blood pressure, it is usually taken at the arm and is held at about the same height as her heart.
If you took your blood pressure at your ankle what would it be relative to your arm?
Higher
Lower
The same
Higher
C. They are equal in weight
B. decrease by 101.3 kPa
Two blocks are of identical size. One which is made of lead sits on the bottom of a pond. The other which is made of wood floats on top. Upon which is the buoyant force greater?
On the lead block
On the wood block
They both experience the same buoyant force
On the lead block
Block a
Block b
Block c
All have the same buoyant force.
Blocks a and c experience the same buoyant force.
All have the same buoyant force.
v1 less than v2
P1 greater than P2
P1 less than P2
What type of function describes simple harmonic motion?
Linear.
Exponential.
Quadratic.
Sinusoidal.
Sinusoidal.
A ball on a massless, rigid rod oscillates as a simple pendulum with a period of 2.0 s. If the ball is replaced with another ball having twice the mass, the period will be
1.0 s
2.0 s
2.8 s
4.0 s
2.0 s
C
C
A and E
Mass A
A, C, E
B and D
A, C, E
A typical earthquake produces vertical oscillations of the earth. Suppose a particular quake oscillates the ground at a frequency of 0.15 Hz. As the earth moves up and down, what time elapses between the highest point of the motion and the lowest point?
1.0 s
3.3 s
6.7 s
13 s
3.3 s
14 cm
16 cm
20 cm
24 cm
14 cm
1.0 s
Which of the following is a longitudinal wave?
Sound wave
Water wave
Light wave
Sound wave
2.0 Hz
1.5 Hz
1.0 Hz
0.5 Hz
0.5 Hz
Which has a longer wavelength?
400-Hz sound wave in air
400-Hz sound wave in water
400-Hz sound wave in water
2.0 m
100 Hz
2.0 s
We measure the sound intensity level in units of
Watts.
Joules.
Hertz.
Decibels.
Decibels.
A 100 Hz sound wave is traveling through the air. If we increase the frequency to 200 Hz, this will ________ the wavelength.
Increase
Not change
Decrease
Decrease
Which of the following is a longitudinal wave?
Sound wave
Water wave
Light wave
Sound wave
D. 0.5 Hz
C. 1.0 m
B. 5
C
An open-closed tube of air of length L has the closed end on the right. Which graph shows the m = 3 standing wave in this tube?
C
An open-open tube of air has length L. Which graph shows the m = 3 standing wave in this tube?
A
The interference of two sound waves of similar amplitude but slightly different frequencies produces a loud-soft-loud oscillation we call
Constructive and destructive interference.
The Doppler effect.
Beats.
Vibrato.
Beats.
For a standing wave in a tube open at each end, the open ends of the tube are
Nodes
Antinodes
Modes
Beats
Nodes
A 170 Hz sound wave in air has a wavelength of 2.0 m. The frequency is now doubled to 340 Hz. What is the new wavelength?
4.0 m
3.0 m
2.0 m
1.0 m
1.0 m
A point on a standing wave that is always stationary is a
Mode
Maximum
Node
Antinode
Node
