Physics Review multiple choice
Given the net forces on and the masses of the blocks shown above, which two blocks have the same acceleration? Select two answers.
A and D Block A and Block D
A water-skier with weight Fg = mg moves to the right with acceleration a. A horizontal tensionforce T is exerted on the skier by the rope, and a horizontal drag force Fd is exerted by the water on the ski. The water also exerts a vertical lift force L on the skier. Which of the following are correct relationships between the forces exerted on the skier-ski system? Select two answers.
C. L-Fg=0
The table shows experimental data of the magnitude of four forces exerted on a 2kg object as it slides across a horizontal surface. Which of the following could represent the magnitude of the net force that is exerted on the object? Select two answers.
A and B 6N and 10N
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.
A and B. Photogates placed at the beginning, end, and at various locations along the track that the car travels on, A meter stick to measure the distance of the track that the car travels on.
An object undergoes an acceleration as it travels along a straight, horizontal section of a track. Which of the following graphs could represent the motion of the object? Select two answers.
A and C X-axis:Time squared Y-axis:Position X-axis:Time Y-axis:Speed
A student must design an experiment to determine the gravitational mass of an object. Which of the following experiments could the student use? Select two answers.
A and D Place the object on one side of a lever at a known distance away from a fulcrum. Place known masses on the other side of the fulcrum so that they are also placed on the lever at known distances from the fulcrum. Move the known masses to a known distance such that the lever is in static equilibrium.Place the object on the end of a vertically hanging spring with a known spring constant. Allow the spring to stretch to a new equilibrium position, and measure the distance the spring is stretched from its original equilibrium position.
A student wants to study the motion of an object that has a constant acceleration. Which of the following experiments could the student conduct to provide the best situations in which an object has a constant acceleration? Select two answers.
A and D Release a ball from rest near Earth's surface; Release a cart from rest such that it travels down an incline of 40 degrees with respect to the ground.
Two blocks, with masses indicated in the figure above, are at rest on a horizontal surface and connected by a string of negligible mass and a compressed spring. There is negligible friction between the blocks and the surface. The string is cut, and the spring pushes the blocks away from each other. Which of the following statements are true about the motion of the blocks immediately after the string is cut? Select two answers.
A and D The velocity of the center of mass of the two-block system is zero; The magnitude of the acceleration of the left block is greater than that of the right block.
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?
A. 0m
A 50.0 N box 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 is 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.
A. 0m/s^2
A meteoroid is in a circular orbit 600 km above the surface of a distant planet. The planet has the same mass as Earth but has a radius that is 90 % of Earth's (where Earth's radius is approximately 6370 km).The acceleration of the meteoroid due to the gravitational force exerted by the planet is most nearly.
A. 9m/s^2 toward the center of the plant
The position as a function of time for two objects moving along a straight line is shown in the graph.Which statement is true about the distances the two object have traveled at time tf?
A. Object 1 has traveled a greater distance
A student wants to determine the coefficient of static friction μ between a block of wood and an adjustable inclined plane. Of the following, the minimum additional equipment the student needs to determine a value for μ is?
A. Protractor only
A satellite of mass m orbits a moon of mass M in uniform circular motion with a constant tangential speed of v.The gravitational field strength at a distance R from the center of moon is gR. The satellite is moved to a new circular orbit that is 2R from the center of the moon. What is the gravitational field strength of the moon at this new distance?
A. gR/4
An object attached to one end of a string moves in a circle at constant speed. Which of the following is correct?
A. the object is accelerating as it moves
Block 1 slides rightward on the floor toward an ideal spring attached to block 2, as shown. At time t1, block 1 reaches the spring and starts compressing it as block 2 also starts to slide to the right. At a later time,t2, block 1 loses contact with the spring. Both blocks slide with negligible friction. Taking rightward as positive, which pair of graphs could represent the acceleration of block 2 and the center-of-mass acceleration of the two-block system?
A.First graph jumps up and back down second graph is flat 0
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?
A.The electric force
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?
A.The track was not level and was tilted slightly downward.
The graphs above represent the position x, velocity v, and acceleration a as a function of time t for a marble moving in one dimension. Which of the following could describe the motion of the marble?
C. Rolling up a ramp and then rolling back down
The inclined plane in the figure above has two sections of equal length and different roughness. The dashed line shows where section 1 ends and section 2 begins. A block of mass M is placed at different locations on the incline. The coefficients of kinetic and static friction between the block and each section are shown in the table below. If the block is at rest on section 1 of the incline, what is the magnitude of the force of static friction exerted on the block by the incline?
A.μs1Mgcosθ
A ladybug is crawling up a wall at constant speed, as shown above. Which of the following are correct justifications for how forces help the ladybug move up the wall? Select two answers.
B and C The ladybug exerts a downward force on the wall to move itself up the wall; The upward force of the wall on the ladybug moves the ladybug up the wall
A block of known mass M is on a disk that rotates about its center, as shown above. The block does not slip on the disk, and travels at a constant tangential speed v when at a distance R from the center with a centripetal force of magnitude F exerted on it. Which of the following statements about other quantities that might be determined is correct?
B and C The centripetal acceleration of the block can be determined, since ac=v2r since the block's tangential speed is known and the radius is known.;The coefficient of friction between the block and the disk can be determined, since friction provides the centripetal force and the equation F=μmg can be applied.
Two blocks are tied together with a string. They are thrown onto a layer of ice such that they spin around their center of mass C as they slide horizontally across the icy surface, as shown in the figure. A graph of the two-block system's velocity as a function of time is shown. Based on the graph, which of the following claims are correct about the system? Select two answers.
B and D The acceleration of the center of mass of the system is constant. The system's acceleration vector is opposite to the direction of the system's velocity vector.
A student sets an object attached to a spring into oscillatory motion and uses a motion detector to record the velocity of the object as a function of time. A portion of the recorded data is shown in the figure above.The total change in the object's speed between 1.0 s and 1.1 s is most nearly.
B. 5cm/s
A block is projected up a frictionless plane with an initial speed vo. The plane is inclined 30° above the horizontal. What is the approximate acceleration of the block at the instant that it reaches its highest point on the inclined plane?
B. 5m/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. 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 balls have traveled half their vertical distance to the floor, what is the acceleration of the center of mass of the two-ball system relative to Earth?
B. Equal to g
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?
B. Position xf is farther away from the sensor than x0, and ax is negative.
During an experiment, a block of mass M=0.20kg 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, vmax, are recorded. A student creates a graph of vmax2 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 μS between the block and the disk?
B.Determine the slope of the best fit line and set it equal to μSg.
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?
B.The tension will double, but the acceleration will stay the same.
An object travels along a straight line across a horizontal surface, and its motion is described by the velocity versus time graph shown in the figure. Which of the following methods will determine the total displacement of the object between 0s and 5s? Select two answers.
C and D Finding the area bounded by the horizontal axis and the curve from 0s to 5s; Using average speed= total distance/total and multiplying the average speed of 5ms by a total time of 5s.
The system shown above is released from rest. If friction is negligible, the acceleration of the 4.0 kg block sliding on the table shown above is most nearly.
C. 3.3m/s^2
Blocks X and Y are glued together and released from rest on a ramp with negligible friction, as shown in trial 1. The blocks are then separated and connected by a light spring, as shown in trial 2. The spring is compressed and the blocks are again released from rest on the ramp. Immediately after the blocks are released, is the net force on the two-block system the same or different between trial 1 and trial 2? Immediately after the blocks are released, is the net force on block Y the same or different between trial 1 and trial 2?
C. Force On system- the same Force on Block Y-Different
The toy car shown in the figure above enters the vertical circular loop with an initial velocity and moves completely around the loop without friction. If the car has no means of self-propulsion, which of the following is true of the car's acceleration at the instant it is at point P?
C. It is directly toward the center of the circle.
A student builds the apparatus shown above. A light string is attached to an object of unknown mass and passed through a tube such that the other end of the string is attached to a second object of mass M. By holding on to the tube, the student swings the object of unknown mass in a horizontal circle of radius r while the object of mass M hanging from the string remains at a constant height. In each trial, the radius r of the circular path is changed and the tangential speed ν of the object of unknown mass is calculated. How can the student determine the value of the unknown mass by using the radius of its circular path and its speed?
C. Use the slope of a graph of v as a function of R
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. By collecting the appropriate data, the students can determine the relationship between the acceleration of the cart and the net force exerted on the cart. Which of the following graphs should the students produce to show the correct relationship?
C. X-axis: Net force Y-axis:Acceleration Straight Line
Two massive, positively charged particles are initially held a fixed distance apart. When they are moved farther apart, the magnitude of their mutual gravitational force changes by a factor of n. Which of the following indicates the factor by which the magnitude of their mutual electrostatic force changes?
C. n
An object of mass 10 kg is released from rest above the surface of a planet 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.
C.35N
A student sets an object attached to a spring into oscillatory motion and uses a motion detector to record the velocity of the object as a function of time. A portion of the recorded data is shown in the figure above.The acceleration of the object at time t = 0.7 s is most nearly equal to which of the following?
C.The area under the curve between where the graph crosses the time axis near 0.63s and time 0.7s
The position as a function of time for two objects moving along a straight line is shown in the graph. At which of the following times do the two objects have the same velocity?
C.tC
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?
D. 25m/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.
D. 6m/s
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?
D. Fab stays the same Fbc increases
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?
D. Less than 9.8 m/s^2 but greater than 0
An astronaut stands on the surface of an asteroid. The astronaut 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 motion of the astronaut?
D. The gravitational force between the astronaut and the astroid.
A spaceship is traveling from Earth to the Moon. Which of the following is true of the gravitational force on the ship due to the two objects when the ship is equidistant from Earth and the Moon?
D. There is a net force because the force exerted by Earth is greater than that exerted by the Moon.
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?
D. There must be another object such that the gravitational forces exerted on the comet are balanced at this location.
Balls 1 and 2 are each thrown horizontally from the same height above level ground, but ball 2 has a greater initial velocity after leaving the thrower's hand. If air resistance is negligible, how do the accelerations of the balls and the times it takes them to hit the ground compare?
E. Acceleration a- Equal; Time to hit ground- Equal