Physics Final Exam
A solid metal ball and a hollow plastic ball of the same external radius are released from rest in a large vacuum chamber. When each has fallen 1m, they both have the same
speed
An object initially at rest falls from a height H until it reaches the ground. Two of the following energy bar charts represent the kinetic energy K and gravitational potential energy Ug of the object-Earth system at two positions. the first position is when the object is initially released, and the second position is when the object is halfway between the release point and the ground. Which two charts could represent the mechanical energy of the object Earth system? Select the two answers.
B. First Graph - all Ug no K, Second Graph - Ug=K
A 2 kg block on a horizontal surface is attached to a horizontal spring of negligible mass. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. The block is released from rest after the spring is stretched such that the block-spring system experiences simple harmonic motion, as shown in the graph that represents the block's velocity as a function of time. How could a student use the known information and the graph to determine the magnitude of the change in spring potential energy of the system from the release point of the block to the moment when the system's spring potential energy is zero?
By determining the kinetic energy of the block at 2s by using K = 1/2mv^2
A block is moving horizontally with a speed of v0 when it encounters a ramp as shown below. Which of the following graphs best represents the position of the block measured from the top of the ramp as a function of time if friction is negligible?
Increasing square graph (half parabola going up positive direction)
The toy car shown in the figure 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?
It has components both downward and toward the center of the circle.
An object's velocity v as a function of time t is given in the graph below. Which of the following statements is true about the motion of the object?
the object's initial and final positions are the same
If the charge of each of two particles is doubled and the separation between them is also doubled, the force between the two particles is
the same as before
A planet with half Earth's mass and half Earth's radius is discovered. What would an astronaut who weighs 800 N on Earth weigh on the planet?
1600 N
Given the circuit below, how do the currents I1, I2, and I3 compare?
I1 > I2 > I3
The frequencies of the first two overtones (2nd and 3rd harmonics) of a vibrating string are f and 3f/2. What is the fundamental frequency of this string?
f/2
The pendulum illustrated below has a length of 2m and a bob of mass 0.4 kg. It is held at an angle, θ, as shown, where cos θ= 0.9. The frequency of oscillation is most nearly:
sqrt(5)(1/2pi) Hz
A thin rod of length d on a frictionless surface is pivoted about one end, as shown below, and can rotate freely. The rod is at rest when it is struck by a sphere with linear momentum of magnitude pi perpendicular to the rod. The sphere rebounds along its original line of motion with momentum of magnitude pf. What is the magnitude of the angular momentum of the rod immediately after collision?
(pf + pi)d
A 1.0 kg block is attached to an unstretched spring of spring constant 50 N/m and released from rest from the position shown below in Fig 1. The block oscillates for a while and eventually stops moving 0.2m below its starting point, as shown in Fig 12. What is the change in potential energy of the block-spring-Earth system between Fig 1 and Fig 2?
-1 J
An object is released from rest near a planet's surface. A graph of the acceleration as a function of time for the object is shown for the 4s after the object is released. The positive direction is considered to be upward. What is the displacement of the object after 2 s?
-10m
A ball is thrown with an initial speed of 20 m/s at an angle 60 to the ground. IF air resistance is negligible, what is the ball's speed at the instant it reaches its maximum height from the ground?
10 m/s
One end of a strong is attached to a vertical pole with the other end of the string attached to a ball that swings in a horizontal circular path as shown. Which of the following free body diagrams represents the forces exerted on the ball?
2 forces in diagram, one going up, and one going vertically right \ 0 |
A student performs and experiment in which two blocks, block X of mass 2 kg and block Y of mass 3 kg, are tied together by a rope as shown above. The system containing Block X and Block Y is dropped above Earth's surface in the orientation as shown above. A motion detector below each block collected data that were graphed to show the velocity as a function of time for blocks X and Y as they fell toward the ground. The graphs are shown in Figure 2 and Figure 3, respectively. The positive direction is considered to be down. The change in momentum for the system containing block X and BlockY is most nearly
250 kg.m/s
During an experiment a student records the net horizontal force exerted on an object moving in a straight line along the horizontal frictionless track. The graph below shows the force as a function of time, Of the following, which is the best approximation of the magnitude of the change in momentum of the object between 0 and 4 s?
30 kg x m/s
What is the tension in the left chain?
375 N
A student rides a bicycle in a circle at constant speed and constant radius. A force diagram for the student-bicycle system is shown in the figure below. The value for each force is shown in the figure. What is the acceleration of the student-bicycle system?
5 m/s^2
A student obtains data on the magnitude of force applied to an object as a function of time and displays the data on the graph below. Answer the following question for the information and the diagram above. The increase in the momentum of the object between t = 0 and t = 4s is most nearly
60 N.s
In the circuit below, the current through the ammeter is 2A. What is the current through the resistor of unknown resistance R?
6A
A transverse wave is traveling on a string. The graph below shows position as a function of time for a point on the string. If the frequency of the wave is doubled, what is the new average speed of the point?
9.6 m/s
A solid metal bar is at rest on a horizontal frictionless surface. It is free to rotate about a vertical axis at the left end. The figures below show forces of different magnitudes that are exerted on the bar at different locations. In which case does the bar's angular speed about the axis increase at the fastest rate?
A) One force acting on bar at the very end
For this question, you must select both correct choices to earn credit. No partial credit will be earned if only one correct choice is selected. Select the two that are best in each case. Do not use a comma between your answers, use uppercase letters. A block of mass m is at rest on a rough incline, as shown in the figure below. Which of the following forces must have a magnitude equal to mg? Select two answers.
A. The total force exerted on the block by the incline D. The gravitational force exerted on Earth by the incline.
The figures below indicate forces acting on a rod in different situations. The lengths of the force vectors are proportional to the magnitudes of the forces. In which situation is the rod in both translational and rotational equilibrium?
B forces going to the right and left from the very top
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 below. 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? A) Protractor B) Meterstick C) Force Probe D) Motion Sensor
BA
A block slides down an inclined plane in a classroom. Which of the following pieces of information are needed to determine whether the velocity of the block will be constant? Select two answers. A. The mass of the block B. The angle of the inclined plane C. The acceleration due to gravity in the classroom D.The coefficient of kinetic friction between the block and the inclined plane
BD
Block X of mass m0 is at rest at the top of a ramp, and the block's center of mass is at a height H1 above the ground. Block X is then released from rest, and it slides down the ramp and collides with block Y of mass m0 which is initially at rest and has its center of mass at a height h above the ground. At the moment before the collision, block X has a speed of v0. After the collision, block Y travels such that it lands at point P.
Because the total momentum of the system does not remain constant, the system is open.
The circuit below contains two resistors R and 2R. The graph shows the total energy E dissipated by the smaller resistance as a function of time. Which of the following shows the corresponding graph for the larger resistance?
C (y-axis is E1/2)
A small object with positive charge Q is fixed in place. A small beat with positive charge q is released from rest from the position shown above. In the absence of forces other than the electric force, which of the following graphs best represents the bead's acceleration as a function of its distance from the fixed object?
C \___>
A disk is initially rotating counterclockwise around a fixed axis with angular speed w0. At time t = 0, the two forces shown in the figure below are exerted on the disk. If counterclockwise is positive, which of the following could show the angular velocity of the disk as a function of time?
C) Linear decreasing crosses x-axis
The figure below shows a block on a horizontal surface attached to two springs whose other ends are fixed to walls. A light string attached to one side of the block initially lies straight across the surface, as shown. The other end of the string is free to move. There is significant friction between the block and the surface but negligible friction between the string and the surface. The block is displaced a distance d and released from rest. Which of the following best represents the shape of the string a short time later?
C, one where wave is smaller closer to the oscillator and bigger farther away from it
A student must determine the inertial mass of a block that is pulled across a horizontal surface using a force probe and accelerometer. The student's data are represented in the graph below What must the student do to determine the inertial mass of the block?
Calculate the slope.
A guitar string of length L can vibrate with antinodes as shown above...
D.Two periodic waves of wavelength 2L/3 , one moving to the left and one moving to the right
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 keeping the tangential speed v0 of the ball constant, as shown below. Which of the following graphs represents the acceleration a of the ball as a function of time, t?
Exponential Increase Graph ---/^
An astronaut with mass MA is within a satellite that orbits Earth at a height H above its surface. Earth has a mass ME and radius RE. Which of the following is a correct expression for the gravitational force exerted on the astronaut by Earth?
F g = G (MEMA)/ (RE +H)^2
When an object X with charge + 2 μ C is 1 meter from object Y with charge − 3 μ C, the magnitude of the force between them is F. Object Y is removed, and object Z with charge − 2 μ Cis placed 2 meters from object X. What is the magnitude of the force between objects X and Z?
F/6
A satellite is a large distance from a planet, and the gravitational force from the planet is the only significant force exerted on the satellite. The satellite begins falling toward the planet, eventually colliding with the planet. As the satellite falls, which of the following claims is correct about how the force that the planet exerts on the satellite Fps changes and how the force that the satellite exerts on the planet Fsp changes if at all? What reasoning supports this claim?
Fps and Fsp both increase. The gravitational forces that two objects exert on one another decrease as the separation between the objects increases, and these forces are always equal in magnitude.
At a point of observation, the time between successive crests of a passing wave is 0.2 s. Which of the. following must be true of the wave?
Its frequency is 5 Hz.
A researcher is analyzing data from a high-energy particle collision. The result of the analysis gives a value of 8.8 x 10 − 19 C ± 0.1 x 10 − 19 for the charge of one of the emitted particles. Should the researcher accept the value?
No because the value is not an integer multiple of the elementary charge.
The figure below represents two guitar strings of different materials and lengths, which are on two guitars of different sizes. String 1 is plucked so it vibrates in the pattern shown. Very soon after string 1 is plucked, string 2, which is a short distance away, vibrates in the pattern shown. The guitars are placed in a sealed chamber and then the air is pumped out of the chamber. String 1 is again plucked and vibrates in the pattern shown. Does string 2 again vibrate in the pattern shown, and why or why not?
No, because almost no energy associated with the vibration of string 1 reaches string 2.
A simple pendulum consisting of a small object of mass m is attached to a string of length L has a period of T. A pendulum with which of the following combinations of object mass and string length will also have a period T?
Object mass = m/2, String length = 1
A student wants to determine the speed of sound at an elevation of one mile. To do this the student performs an experiment to determine the resonance frequencies of a tube that is closed at one end. The student takes measurements every day for a week and gets different results on different days. Which of the following experiments would help the student determine the reason for the different results?
Repeating the experiment on several 10oC days and several 20oC days.
A rock attached to a string swings in a vertical circle, as shown below, with negligible air resistance. Which of the following diagrams could correctly show all the forces on the rock when the string is in the position shown?
Sphere with arrow down and arrow point left <-------o |
An astronaut performs an experiment near the surface of a moon by releasing an object at rest above a motion detector such that data can be collected about the object's vertical velocity as a function of time. The data are provided in the table. Which of the following graphs most likely represents the shape of the curve of the magnitude of the gravitational field strength near the surface of the moon as a function of time? Table of Time and Vertical Velocity
Straight Line that is NOT on the x-axis
A potato falling vertically downward is struck by a dart that is traveling vertically upward, as shown above. The dart and potato then collide, stick together, and continue moving after the collision. Consider the dart-potato system. Which of the following graphs best represents the speed v of the center-of-mass of the dart-potato system, as a function of time t, before, during, and after the collision?
Straight Linear Graph going up is correct answer
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 the Earth?
The force exerted on the astronaut by the Earth is equal to the force exerted on the Earth by the astronaut.
A person is running on a track. Which of the following forces propels the runner forward?
The force of friction exerted by the ground on the person
When the circuit below is set up, the potential difference across the battery is 3.0V. By how much will the magnitude of the potential difference across R2 change when R3 is removed and its branch is left open?
The magnitude of the potential difference across R2 increases by 0.5V.
Two identical books are stacked on a table. A third identical book is then placed on top of the first two, causing an increase in the normal force exerted by the bottom book on the middle book. Which of the following is a correct explanation for the increase in this normal force?
The third book produces an additional downward force on the middle book, thus increasing the upward force exerted by the bottom book to maintain equilibrium.
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 0.4 kg. When placed on a balance, the cart's mass is found to be 0.5 kg. Which of the following could explain the difference in mass?
The track was not level and was tilted slightly downward.
Two strings differing only in length are attached to the same oscillator, as shown in the figure below. Both are fixed at the other end and are under the same tension. The oscillator creates a transverse wave and is adjusted to the lowest frequency that creates a standing wave on the shorter string. Which of the following explains why there will not be a standing wave on the longer string?
The wavelength associated with the given frequency does not match the boundary conditions set by the length of the longer string.
The figure below shows the position of a moon that orbits a planet in an elliptical path. Two specific locations of the moon, position A and position B, are labeled. In what direction is the net force exerted on the moon?
Toward the planet.
An isolated system consists of the two particles shown below. Particle 1 has charge +q and mass m. Particle 2 has charge +2q and mass 2m. The ratio of the magnitude of the electrical force on particle 1 to the magnitude of the electrical force on particle 2 is
1
A block of mass 3 kg slides along a horizontal surface that has negligible friction except for one section, as shown below. The block arrives at the rough section with a speed of 5 m/s and leaves it 0.5 s later with a speed of 3 m/s. What is the magnitude of the average frictional force exerted on the block by the rough section of the surface?
3N
A system consists of a disk rotating on a frictionless axle and a piece of clay moving toward it, as shown in the figure below. The outside edge of the disk is moving at a linear speed v, and the clay is moving at speed v/2. The clay sticks to the outside edge of the disk. How does the angular momentum of the system after the clay sticks compare to the angular momentum of the system before the clay sticks, and what is an explanation for the comparison?
It is the same because there is no external torque acting on the system.
Object X travels across a horizontal surface and collides with object Y. The velocity as a function of time for object X and object Y before, during, and after the collision is shown in the graph below. Both objects have a mass of 2 kg. Which of the following correctly describes the momentum p of the system and the kinetic energy K of the system?
Momentum conserved, Kinetic energy not conserved
A 4 kg object moving to the left collides with and sticks to a 3 kg object moving to the right. Which of the following is true of the motion of the combined objects immediately after the collision?
The motion cannot be determined without knowing the speeds of the objects before the collision.
A student measures an object of unknown mass that oscillates horizontally at the end of an idea spring. The student measures the object's period of oscillation with a stopwatch. While the object continuously oscillates, the student determines the maximum speed of the object during two oscillations. The first speed is 3.5 m/s and the second speed is 2.7 m/s, Which of the following could account for the decrease in the object's maximum kinetic energy?
The object-spring system lost energy to its surroundings.
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 negligibe, how do the accelerations of the balls and the times it takes them to hit the ground compare?
acceleration equal, time to hit the ground equal
A sphere of mass m1, which is attached to a spring, is displaced downward from its equilibrium position as shown below left and released from rest. A sphere of mass m2, which is suspended from a string of length L is displaced to the right as shown below right and released from rest so that it swings as a simple pendulum with small amplitude. Assume that both spheres undergo simple harmonic motion. If both spheres have the same period of oscillation, which of the following is an expression for the spring constant?
m1g/L
The figure below shows a portion of a periodic wave on a string at a particular moment in time. The vertical arrows indicate the direction of the velocity of some points on the string. Is the wave moving to the right or to the left?
to the left
A person driving a car suddenly applies the brakes. The car takes 4 s to come to rest while traveling 20 m at constant acceleration. Can the speed of the car immediately before the brakes were applied be determined without first determining the car's acceleration?
yes, by determining the average speed while braking and double it
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
0 m/s^2
A 2 kg object is a distance of 10,000,000 m away from the center of Earth, which has a mass of nearly 6 x 1024 kg. What is the approximate gravitational field strength of Earth's gravitational field at the location of the 10kg object?
4 N/kg
An object with mass m is suspended at rest from a spring with a spring constant of 200 N/m. The length of the spring is 5.0 cm longer than its unstretched length, L, as shown below. A person then exerts a force on the object and stretches the spring an additional 5.0 cm. What is. the total energy stored in the spring at the new stretched length?
1.0 J
A horizontal, uniform board of weight 125 N and length 4 m is supported by vertical chains at each end. A person weighing 500 N is sitting on the board. The tension in the right chain is 250 N. How far from the left end of the board is the person sitting?
1.5 m
For another, identical object initially at rest, no frictional force is exerted during segment 2 (between t = 2 s and t = 4s). A rope exerts the same constant force of magnitude FT as in the previous scenario. What is the change in the object's kinetic energy during segment 2?
12 J
An axle passes through a pulley. Each end of the axle has a string that is tied to a support. A third string is looped many times around the edge of the pulley and the free end attached to a block of mass mb, which is held at rest.When the block is released, the block falls downward. Consider clockwise to be the positive direction of rotation, frictional effects from the axle are negligible, and the string wrapped around the disk never fully unwinds. The rotational inertia of the pulley 1/2 MR2 is about its center of mass.
4 forces, 1 torque
An Atwood's machine is set up by suspending two blocks connected by a string of negligible mass over a pulley, as shown below. The blocks are initially held at rest and then released at time t0 = 0 s. The speed of the 3.0 kg block at time t1 = 2.0 s is most nearly
4.0 `m/s
The two blocks of masses M and 2M shown below initially travel at the same speed v but in opposite directions. They collide and stick together. How much mechanical energy is lost to other forms of energy during the collision?
4/3Mv^2
The Atwood machine shown consist 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 mass. The block of mass m1 is a distance h1 above the ground, and the block of mass m2 is a distance h2 above the ground. M2 is larger than m1. The two-block system is released from rest. Which of the following claims correctly describes the outcome after the blocks are released from rest but before the block of mass 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 gravity on the system. B. For the system consisting of the two blocks, the change in the kinetic energy of the system is equal to the sum of m1gh1 + m2gh2. C. For the system consisting of the two blocks, the change in the kinetic energy of the system is equal to the decrease in the gravitational potential energy of the system. D, For the system consisting of the two blocks, the pulley and the Earth, the change in the total mechanical energy of the system is zero.
CD
The graph below shows velocity v as a function of time t for a 0.5 kg object traveling along a straight line. The graph has three segments labeled 1, 2, and 3. A rope exerts a constant force of magnitude FT on the object along the direction of motion the whole time. During Segment 2 only, a frictional force of magnitude Ff is also exerted on the object. Which of the following expressions correctly relates the magnitudes of Ff and FT?
FT < Ff < 2FT
Two protons are held a distance d apart. The electrostatic force and the gravitational force that one proton exerts on the other are Fe and Fg respectively. Which of the following correctly compares the magnitude and direction of these forces?
Fe> Fg, opposite direction
The diagram above represents the forces exerted on a box the child is holding. FN represents the force applied by the child's hand and Fg represents the weight of the box. The child begins to raise the box with increasing speed. Which of the following claims is correct about force Fh that is exerted by the box on the child's hand as the box is being raised?
Fh= FN where FN is larger as the box is being raised than when it was held.
Two wave pulses are created simultaneously at opposite ends of a string and move toward the center of the string, as shown in the figure below. Both pulses have the same width. The labeled figures show possible shapes of the string at different moments in time. Which of the following indicates a correct time order for the shape of the string as the pulses move along the string, come together, and move apart?
Figure X, Figure W, Figure Y
A steel ball supported by a stick rotates in a circle of radius r, as shown below The direction of the net force acting on the ball when it is in the position shown is indicated by which of the following?
Force is pointing to the center of the circle (E?)
A person throws a marble straight up into the air, releasing it a short height above the ground and catching it at that same height. If air resistance is negligible, which of the following graphs of position y vs time x is correct for the motion of the marble as it goes up and then comes down?
Frowning Parabola
Tiny drops of oil that have different amounts of electric charge produced by a random process are sprayed into a region between a positively and a negatively charged plate. The charge on each drop is determined by analyzing the effect of the electric force on the drop/s motion. Two graphs of the number of drops as a function of the charge on each drop, where e is the charge of an electron, are shown below. Which graph shows the most likely result after repeating the experiment many times and why?
Graph 1, because it shows that within experimental error charges only exist in multiples of e
Consider the situation in which object X as a speed of 2 m/s and object Y has a speed of 5 m/s after the collision takes place. After the collision both objects travel in the same direction. Which of the following predictions must be true about how the momentum p of the two-object system and the kinetic energy K of the two object system change before the collision to after the collision? You Answered
Momentum remains constant, Kinetic energy remains constant.
The diagram below shows a top view of a child of mass M on a circular platform of mass 5M that is rotating counterclockwise. Assume the platform rotates without friction. Which of the following describes an action by the child which will result in an increase in the total angular moment of the child-platform system?
None of the actions described will change the total angular momentum of the system.
A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 below. 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 of 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 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? - Equal to g Which of the following conclusions can the student draw from the graphs,and why? - Since both balls have the sane vertical position at any given time, they reach the ground at the same time.
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 basket fall, the kitten rolls, turns, kicks, and catches the basket in 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 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 farther away from Earth's surface than before. Which of the following best describes the effects of these changes on Earth's gravitational field strength at the space station's new location?
The increase in mass of the space station has no effect on the field strength, and the increase in orbital radius decreases the field strength.
A sphere of mass m1, which is attached to a spring, is displaced downward from its equilibrium position as shown below left and released from rest. A sphere of mass m2, which is suspended from a string of length L is displaced to the right as shown below right and released from rest so that it swings as a simple pendulum with small amplitude. Assume that both spheres undergo simple harmonic motion. Which of the following is true for both spheres?
The maximum kinetic energy is attained as the sphere passes through its equilibrium position.
A student plans to conduct an experiment in which the momentum of a two object system can be determined immediately before and after a collision takes place. The student slides block X at an unknown constant speed toward an identical block, block Y, that is initially at rest as shown in the figure below. There is negligible friction between the blocks and the surface.
The momentum of the two-block system is not conserved because the initial momentum of the system is not equal to the final momentum of the system.
A spacecraft is placed in a circular orbit around a planet with a mass of 6.4 x 1023 kg. The spacecraft orbits at a height of 4.5 x 107 m above the planet's surface. What additional information is needed to calculate the speed of the spacecraft in orbit?
The planet's radius only.
A student predicts that a box sliding down a ramp inclined at 45 degrees should have an acceleration of approximately 7 m/s2.The block is released from rest and the student measures the distance the block travels and the time it takes to travel that distance. The student determines that the block's acceleration is only 5.5 m/s2. Which of the following is the most likely reason for the difference between the predicted and calculated accelerations?
The student's model used to make the prediction did not account for all of the forces that are exerted on the block.
Two objects of the same mass travel in the same direction along a horizontal surface. Object X has a speed of 5 m/s and object Y has a speed of 2 m'/s as shown in the figure below. After a period of time, object X collides with object Y. Consider the situation in which the objects collide but do not stick together. Which of the following predictions is true about the center of mass of the two object system immediately after the collision?
The velocity of the center of mass does not change
In one experiment, a student rolls a 2 kg ball such that it collides with a wall with a force of 10,000 N. In a second experiment, the student rolls a 5 kg ball such that it collides with the wall at a force of 5000 N. In both experiments, the balls bounce back from the wall and eventually come to rest. Which of the following statements is true regarding the force that the wall exerts on each ball?
The wall exerts a greater force on the 2 kg ball than on the 5 kg ball since the force from the wall on each ball is equal to the force that each ball exerts on the wall.
An object of charge 2.0 e must be discharged, where e is the elementary value of charge. The rate of discharge of the object is 1.0 e/s. A scientist claims that the object is successfully discharged at a time that is equal to or less than 2.0s. Which of the following tables shows the charge of the object as a function of time?
Time: Charge: 0 2.0e 0.5 2.0e 1.0 1.0e 1.5 1.0e 2.0 0.0
The horizontal wire shown on the right in the figure below will break when the tension in it exceeds the value Tmax. What is the maximum mass M that the hanging object can have without the horizontal wire breaking? (Assume the wire on the left does not break prior to the horizontal wire breaking.)
Tmaxtan(theta)/g
A massless rigid rod of length 3d is pivoted at a fixed point W, and two forces each of magnitude F are applied vertically upward as shown below. A third vertical force of magnitude F may be applied, either upward or downward, at one of the labeled points. With the proper choice of direction at each point, the rod can be in equilibrium if the third force of magnitude F is applied at the point
V or X only
An object begins at position x = 0 and moves one-dimensionally along the x-axis with a velocity v expressed as a function of time t according to the graph below. At what time does the object pass through x = 0 again?
between 20 s and 30 s
A box of mass m is initially at rest at the top of a ramp that is at an angle θ with the horizontal. The block is at a height h and length L from the bottom of the ramp. The block is released and slides down the ramp,. The coefficient of kinetic friction between the block and the ramp is μ. What is the kinetic energy of the box at the bottom of the ramp?
mgh - Mu mgL cos theta
