Physics Final Review

A bowling pin is thrown vertically upward such that it rotates as it moves through the air, as shown in the figure. Initially, the center of mass of the bowling pin is moving upward with a speed vi of 10 m/s. The maximum height of the center of mass of the bowling pin is most nearly...

vi^2/2g

Three blocks, A, B, and C, are pushed by a constant force F that is applied on block A as shown. There is negligible friction between the blocks and the surface. When a small object is attached to the top of block B, the normal force between blocks A and B is FAB and the normal force between blocks B and C is FBC. How will the values of FAB and FBC change if the small object is moved to the top of block C and the experiment is repeated?

FAB decreases, FBC increases

During an experiment, an object is placed on a disk that rotates about an axle through its center, as shown in Figure 1. The disk is a distance R = 0.10 m from the center and rotates with a constant tangential speed of 0.60 m/s. A free body diagram of the forces exerted on the block is shown in Figure 2 with an unknown force of friction. What is the force of friction exerted on the object.

0.72 N

A car initially at rest accelerates at 10m/s^2. The car's speed after it has traveled 25 meters is most nearly

22.0 m/s

A planet travels in an elliptical orbit around its star, as shown above. Which arrow best shows the direction of the net force exerted on the planet?

C

The motion of a particle along a straight line is represented by the position versus time graph above. At which of the labeled points on the graph is the magnitude of the acceleration of the particle greatest?

C

A rock attached to a string swings in a vertical circle, as shown above, with negligible air resistance. Which of the following diagram as could correctly show all the forces on the rock when the string is in the position above?

C or the hands from 6 to 9

An object is moving to the right with speed vi when a force of magnitude F is exerted on it. In which of the following situation is the object's direction of motion changing and kinetic energy decreasing at the instant shown?

D or 120 degree angle between F and vi

A ball of mass M swings in a horizontal circle at the end of a string of radius R at a constant tangential speed v0. A student gradually pulls the string inward such that the radius of the circle decreases while keep the tangential speed v0 of the ball constant, as shown above. Which of the following graphs best represents the acceleration a of the ball as a function of time t?

Exponentially up from hovering around bottom then up

An artificial satellite orbits Earth at a speed of 7800 m/s and a height of 200 km above Earth's surface. The satellite experiences an acceleration due to gravity of

Less than 9.8 m/s^2 but greater than zero

One end of a string is attached to the ceiling with the other end attached to a toy. The toy can be set into motion such that it travels in a horizontal circular path at a constant tangential speed, as shown above. Which of the following measuring tools, when used together, could be used to determine the time it takes for the toy to complete one revolution around the circle? Select two answers.

Meterstick and Protractor

A ball of mass m is attached to vertical rod by two massless strings. The rod is rotated about its axis so that both strings are taut; with tensions T1 and Tz respectively: The strings and rod form the right triangle shown the figure above. The ball rotates in horizontal circle of radius rwith speed What is the tension T1 in the upper string?

Mg/cos theta

An astronaut in deep space is at rest relative to a nearby space station. The astronaut needs to return to the space station. A student makes the following claim: "The astronaut should position her feet pointing away from the space station. Then, she should repeatedly move her feet in the opposite direction to each other. This action will propel the astronaut toward the space station." Is the student's claim correct? Justify your selection.

No. The astronaut's feet are not exerting a force on another object, so there is not external force to accelerate the astronaut towards the space station.

A student is provided with a battery-powered toy car that the manufacturer claims will always operate at a constant speed. The student must design an experiment in order to test the validity of the claim. Which of the following measuring tools can the student use to test the validity of the claim? Select two answers.

Photogates placed at the beginning, end, and at various locations along the track that the car travels on. A meterstick to measure the distance of the track that the car travels on

A spaceship travels from a planet to a moon and passes through the the three A, B, and C, show above. Position B is midway between the centers of the planet and the moon. The planet has a larger mass than the moon. At which location could the net gravitational force exerted on the spaceship be approximately zero.

Position C

Refer to the following material for answering group of questions. A crate in on a horizontal frictionless surface. A force of magnitude F is exerted on the crate at an angle theta to the horizontal, as shown in the figure above, causing the creat to slide to the right. The surface exerts a normal force of magnitude FN on the create. As the crate slides a distance d, it gains an amount of kinetic energy K. While F is kept constant, the angle theta is now doubled but its still less than 90. Assume the crate remains in contact with the surface.

The normal force is less than Fn

An object is moving along a straight, flat a section of track. The net force acting on the object as a function of position is shown int he graph, where the positive direction is in the direction of motion of the object. Assuming the object moves from position x = 0 to x = 7d0 without stopping or moving backward, which of the following statements about its motion are correct? Select two answers.

The object has it's greatest kinetic energy at position 5d0. The object has the same kinetic energy at postion d0 that is had at position 7d0

An object attached to one end of a string moves in a circle at a constant speed. Which of the following is correct?

The object is accelerating as it moves.

The force diagram above shows a box accelerating to the right on a horizontal surface of negligible friction. The tension T is exerted at an angle of 30° above the horizontal. If μ is the coefficient of kinetic friction between the box and the surface, which of the following is a correct mathematical equation derived by applying Newton's second law to the box?

a=(Tcosθ - μ(Mg-Tsinθ))/M

Block X of mass M is attached to block Y of mass 2M by a light string that passes over a pulley of negligible friction and mass, as shown above. In which direction will the center of mass (COM) of the two-block system move after it is released from rest, and what is the magnitude of the acceleration a of block X ?

down and to the right; 2g/3

A moon orbits an isolated planet in deep space. Which of the following forces that the planet exerts on the moon can be considered as negligible?

electric force

Students work together during an experiment about Newton's laws. The students use a setup that consists of a cart of known mass connected to one end of a string that is looped over a pulley of negligible friction, with its other end connected to a hanging mass. The cart is initially at rest on a horizontal surface and rolls without slipping when released. The inertia of the cart's wheels is negligible. Students have access to common laboratory equipment to make measurements of components of the system. The students double the mass that hangs from the string. They also replace the original cart with a new cart that has double the mass. By doubling both masses, how will the tension in the string and the acceleration of the cart change?

linear line pointing up

An object is sliding to the right along a straight line on a horizontal surface. The graph shows the object's velocity as a function of time. What is the object's displacement during the time depicted in the graph?

0 m

A 50.0 N is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is 0.50, and the coefficient of kinetic friction of 0.30. A horizontal 20.0 N force is then exerted on the box. The magnitude of the acceleration of the box is most nearly

0 m/s^2

The figure above shows the net force exerted on an object as a function of the position of the object. The object starts from rest at position x = 0 m and acquires a speed of 3.0 m/s after traveling a distance of 0.090 m. What is the mass of the object?

0.060 kg

At time t = 0, a moving cart on a horizontal track is at position 0.5 m. Using a motion detector, students generate a graph of the cart's velocity as a function of time, as shown above. At t = 2.5 s, the cart's position is most nearly

1.75

What is the kinetic energy of a satellite of mass m in that orbits the Earth, of mass M in a circular orbit of radius R.

1/2 GMm/R

A student is observing an object of unknown mass that is oscillating horizontally at the end of an ideal spring. The student measures the object's period of s hill action with a stopwatch. Using a number of measurements, the student determines the following. The total energy of the object-spring system is most nearly

3.8 J

An object of mass 10 kg is released from rest above the surface of a plant such that the object's speed as a function of time is shown by the graph above. The force due to gravity exerted on the object is most nearly.

35 N

An Atwood's machine is set up by suspending two blocks connected by a string of negligible mass over a pulley, as shown above. The blocks are initially held at rest and then released at time t0 = 0s. The speed of the 3kg block at time t1 = 2.0s is most nearly

4

In a lab, a block weighing 80 N is attached to a spring scale, and both are pulled to the right on a horizontal surface, as shown above. Friction between the block and the surface is negligible. What is the acceleration of the block when the scale reads 32 N.

4 m/s^2

A block is projected up a frictionless plane with an initial speed v0. The plane is inclined 30 degrees above the horizontal. What is the approximate acceleration of the block at the instant that it reaches its highest point on the inclined plane.

5 m/s^2 down the incline

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. In Experiment 1, what is the speed of the ball the instant it makes contact with the ground?

5.4 m/s

A student rides a bicycle in a circle at a constant speed and constant radius. A force diagram for the student-bicycle system is shown in the figure above. The value for each force is shown in the figure. What is the acceleration of the student-bicycle system?

5m/s^2

The graph above represents position x versus time t for an object being acted on by a constant force. The average speed during the interval between 1 s and 2 s is most nearly

6 m/s

A ball is released from rest from the twentieth floor of a building. After 1 s, the ball has fallen one floor such that it is directly outside the nineteenth-floor window. The floors are evenly spaced. Assume air resistance is negligible. What is the number of floors the ball would fall in 3s after it is released from the twentieth floor?

7 to 10 floors

A stone disk is sliding on frictionless ice to the west with speed v, as shown in the figure above. As the disk slides by, a child uses a rubber mallet to hit the disk at point X, exerting a force directly toward the center of the disk. The child hits point X every half second for about 10s, changing the trajectory of the disk but not causing it to rotate. Which of the following most closely approximates the path of the disk while the child is hitting it?

A parabolic path

A student performs an experiment in which the horizontal position of a toy car is recorded on ticker tape from a device that places dots on the tape in equal time intervals. The series of dots in the figure represents the motion of an object moving from the negative direction to the positive direction along the horizontal direction. The time interval between each recorded dot is 1 s. Which of the following experiments could the students have conducted to create the data shown on the ticker tape?

A toy car that initially increases its speed, travels at a constant speed, and then decreases its speed

The Atwood's machine shown consists of two blocks of mass M1 and m2 that are connected by a light string that passes over a pulley of negligible friction and negligible from rest. Which of the following claims correctly describes the outcome after the blocks are released from rest but before the block of m2 reaches the ground? Select two answers.

A. For the system consisting of the two blocks, the change in the kinetic energy of the system is equal to the work done by the gravity on the system C. For the system consisting of the two blocks and the pulley, the increase in kinetic energy of the system is equal to the decrease in the gravitational potential energy of the system.

A block of mass M is at rest on a ramp that is inclined at an angle theta with respect to the horizontal. Frictional forces are considered to be no negligible. The block is pushed against a spring and then held in place. The spring is compressed a distance of x1, and the spring is not secured to the block. The block is then released from rest, travels up the incline, and comes to rest after traveling a distance D, as shown above. Which of the following claims correctly describes the energy of the system under consideration from when the block compressed the spring and when the block has traveled a distance D along the incline? Select two answers.

A. The mechanical energy of the system consisting of the block does not change C. The mechanical energy of the system consisting of the block and Earth increases by more than zero but less than 1/2 kx^21

An object of mass m is attached to a spring on a frictionless incline plane that make an angle theta with the horizontal, as shown above. The object is released from rest with the spring in its unstretched position. As the object moves on the plane, its displacement from the unstretched position is x. What is the magnitude of the work done by gravity as the object slides down the incline?

A: Mgx sin(theta)

During an experiment, a block of mass M = 0.20 kg is placed on a disk that rotates about an axle through its center, as shown in the diagram. The block is moved to different distances R from the axle, and the tangential speed of the block is gradually increased until the mass begins to slip. The distance and maximum tangential speed before slipping, v max, are recorded. A student creates a graph of vmax^2 as a function of R, as shown. How should the student use the graph to most accurately determine the experimental value of the coefficient of static friction us between the block and the disk?

Determine the slope of the best fit line and set it equal to usg

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. Suppose that Experiment 1 and Experiment 2 are conducted at the same time; one student drops the ball from rest at the same instant that a second student horizontally rolls an identical off the table. After both ball have traveled half their vertical distance tot he floor, what is the acceleration of the center of mass of the two-ball system relative to earth

Equal to g

A satellite of mass m and speed v moves in a stable, circular orbit around a planet of mass M. What is the radius of the satellite's orbit?

GM/v^2

A box of mass m is released from rest and accelerates down a ramp that is at an angle theta to the horizontal, as shown. The coefficient of kinetic friction between the box and ramp is u. As the box is sliding down the ramp, how are the magnitudes of the horizontal and vertical components of the box's velocity changing, if at all.

Horizontal Component = Increasing Vertical Component = Increasing

Three forces act on an object. If the object is in translational equilibrium, which of the following must be true? I. The vector sum of the three forces must equal zero II. The magnitudes of the three forces must be equal III. All three forces must be parallel.

I only

A block released from rest at position A slides with negligible friction down an inclined track, around a vertical loop, and then along a horizontal portion of the track, as shown above. The block never leaves the track. Which of the following is true of the net force on the block when it is at position C?

It has components both to the left and vertically downward

Which of the following is constant for an object in uniform circular motion

Kinetic energy

A student must determine the relationship between the inertial mass of an object, the net force exerted on the object, and the object's acceleration. The student uses the following procedure. The object is known to have an inertial mass of 1.0kg. Step 1: Place the object on a horizontal surface such that frictional forces can be considered to be negligible. Step 2: Attach a force probe to the object. Step 3: Hang a motion detector above the object so that the front of the motion detector is pointed toward the object and is perpendicular to the direction that the object can travel along the surface. Step 4: Use the force probe to pull the object across the horizontal surface with a constant force as the force probe measures force exerted on the object. At the same time, use the motion detector to record the velocity of the object as a function of time. Step 5: Repeat the experiment so that the object is pulled with a different constant force. Can the student determine the relationship using this experimental procedure?

No, because the motion detector should be oriented so that the object moves parallel to the line along which he front of the motion detector is aimed

Two objects, X and Y, accelerate from rest with the same constant acceleration. Object X accelerates for twice the time as object Y. Which of the following is true of these objects at the end of their respective periods of acceleration?

Object X has traveled four times as far as object Y.

Two bricks are stacked on a floor. A student draws the force diagram for brick 2, as shown above. The forces are an upwards normal force, a downward force exerted by brick 1, and a downward gravitational force. How many of the forces, if any, in the force diagram are contact forces caused by microscopic interactions.

Only two

A motion sensor is used to create the graph of a student's horizontal velocity as a function of time as the student moves toward and away from the sensor, as shown above. The positive direction is defined as the direction away from the sensor. Which of the following describes the student's final position xf in relation to the starting position x0 and the student's average horizontal acceleration ax between 0.0 s and 3.0s?

Position xf is farther away from the sensor than x0, and ax is negative

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. Which of the following conclusions can the student draw from the graphs, and why?

Since the balls have the same vertical position at any given time, they reach the ground at the same time.

A satellite of mass m orbits a moon of mass M in uniform circular motion with a constant tangential speed of v. The satellite orbits at a distance R from the center of the moon. Which of the following is a correct expression for time T it takes the satellite to make one complete revolution around the moon.

T = 2pi(sqrtr^3/GM)

A kitten sits in a lightweight basket near the edge of a table. A person accidentally knocks the basket off the table. As the kitten and the basket fall, the kitten rolls, turns, kicks, and scratches in the basket with its claws. The basket lands on the floor with the kitten safely inside. If air resistance is negligible, what is the acceleration of the kitten-basket system while the kitten and basket are in midair?

The acceleration is directed downward with magnitude equal to g because the system is a projectile.

A book is at rest on the top of a table. A student makes the following claim: "An attractive electromagnetic force is exerted on the book from the table, and this force can also be classified as the normal force." Which of the following statements correctly justifies the student's claim?

The claim is incorrect because the charged particles of the table exert an upward repulsive force on the charged particles of the book.

A person holds a 4.0 kg block at position A shown above on the left, in contact with an uncompressed vertical spring with a spring constant of 500 N/m. The person gently lowers the block from rest at position A to rest at position B. Which of the following describes the change in energy of the block-spring-Earth system as a result of the block being lowered?

The energy decreased by approximately 1.5 J.

A space station has a mass M and orbits Earth in a circular orbit at a height above Earth's surface. An astronaut in the space station appears weightless because the astronaut seems to float. Which of the following claims is true about the force exerted on the astronaut by Earth?

The force exerted on the astronaut by Earth is equal to the force exerted on Earth by the astronaut.

An astronaut stands on the surface of an asteroid. The student then jumps such that the astronaut is no longer in contact with the surface. The astronaut falls back down to the surface after a short time interval. Which of the following forces cannot be neglected when analyzing the most ion of the astronaut?

The gravitational force between the astronaut and the asteroid

A planet has two moons, Moon A and Moon B, that orbit at different distances from the planet's center, as shown. Astronomers collect data regarding the planet, the two moons, and their obits. The astronomers are able to estimate the planet's radius and mass. The masses of the two moons are determined to be 2M for Moon A and M for Moon B. It is observed that the distance between Moon B and the planet is two times that of the distance between Moon A and the planet. How does force exerted from the planet on Moon A compare to the force exerted from the planet on Moon B?

The gravitational force exerted from the planet on Moon A is eight times larger than the gravitational force exerted from the planet on Moon B .

A ball is moved from Earth to a planet that has a gravitational acceleration that is double that of Earth. How does the gravitational force on the ball when it is on the new planet compare to the gravitational force on the ball when it is on Earth?

The gravitational force on the ball when it is on the new planet is double the force on the ball when it is on Earth.

An amusement park ride has two identical carriages that revolve around the center of the ride's axle, as shown in the figure. Both carts travel at a constant tangential speed at all points along the circular path. At what position is the total mechanical energy of the cart-cart-Earth at its maximum value.

The total energy of the Earth-Ferris wheel ride is constant

A space station has a mass M and orbits Earth in a circular orbit at a height above Earth's surface. A payload of mass m, where m<M, is delivered to the space station. Soon after, the space station's orbit is adjusted so that it is 50 km father away from Earth's surface than before. Which of the following best describes the effects of these changes on Earth's gravitation field strength at the space station's new location.

The increase in mass of the space station has not effect on the field strength, and the increase in orbital radius decrease the field strength.

A student conducts an experiment in which a 0.5kg ball is spun in a vertical circle from a string of length 1 m, as shown in the figure. The student uses the following equation to predict the force of tension exerted on the ball whenever it reaches the lowest point of its circular path at a known tangential speed for various trials. When the experiment is conducted, the student uses a force probe to measure the actual force of tensions exerted on the ball. Why is the predicated force of tension different than the actual force of tensions?

The student did not account for the downward force due to gravity at the ball's lowest point along its circular path, so the predicted force of tension is the net centripetal force exerted on the ball.

A block of mass M is released from rest at point 1, as shown in the figure. The block slides without frictional forces along the circular arc but encounters frictional forces as soon as it reaches the horizontal portion of the track at point 2. The block travels a distance D along the horizontal track before coming to rest at point 3. Consider the block-Earth system. In terms of the mechanical energy of the system, which of the following claims is correct, and why?

The system is open, because there is a net force exerted on the block

A person holds a book at rest a few feet above a table. The person then lowers the book at a slow constant speed and places it on the table. Which of the following accurately describes the change in the total mechanical energy of the Earth-book system?

The total mechanical energy decreases, because the person does negative work on the book by exerting a force on the book in the direction opposite to its displacement.

An inclined track is secured to a table. The height of the highest point of the track above the tabletop is h1. The height from the tabletop to the floor is h2. A block of mass M is released from rest and slides down the track such that all frictional forces are considered to be negligible. The block leaves the track horizontally and stricken the ground at a distance D from the edge of the track as shown. Which of the following statements is correct about the scenario? Select two answers.

The total mechanical energy of the system contains only the block increases from the moment of release to the moment it strikes the ground, the total mechanical energy of the total system remains constant

A cart with an unknown mass is at rest on one side of a track. A student must find the mass of the cart by using Newton's second law. The student attaches a force probe to the cart and pulls it while keeping the force constant. A motion detector rests on the opposite end of the track to record the acceleration of the cart as it is pulled. The student uses the measured force and acceleration values and determines that the cart's mass is 0.4kg. When placed on a balance, the cart's mass is found to be 0.5kg. Which of the following could explain the difference in mass?

The track was not level and was tilted slightly downward

A comet passes by a planet with a speed vo such that the comet travels in a straight line at the instant shown in the figure. The comet's tangential acceleration, centripetal acceleration, and force due to gravity from the planet at this location are provided in the table. Astronomers observe that the comet continues to travel in a nearly straight line, even though calculations show that the gravitational force exerted by the planet should cause the comet to move in a circular orbit. Why does the comet not travel in a circular path around the planet after the instant shown in the figure?

There must be another object such that the gravitational forces exerted on the comet are balanced at this location.

In Figure 1, cart Y is connected to cart X by a tight string and is also connected to the hanging block of mass m0 by a light string that passes over a pulley. Figure 2 shows a system that is identical except for one change: cart Y and X are connected by a spring at its equilibrium length. Both systems are released from rest. Is the hanging block's acceleration as a function of time the same in both systems, and why or why not.

Yes, because the net external force exerted on both systems is true