Physics 111 Final Exam
A ferry can travel at an optimal speed of 8 km/h in still water measured relative to the shore. What is the optimal speed of the ferry, relative to the shore, if it moves perpendicular to a 6 km/h current? A. 10 km/h B. 4 km/h C. 14 km/h D. 2 km/h
A. 10 km/h
A boat that can travel at 4.0 km/h in still water crosses a river with a current of 2.0 km/h. At what angle must the boat be pointed upstream (that is, relative to its actual path) to go straight across the river? A. 30 degrees B. 63 degrees C. 27 degrees D. 60 degrees
A. 30 degrees
A motorcycle has a velocity of 24 m/s, due south as it passes a car with a velocity of 15 m/s due north. What is the magnitude and direction of the velocity of the motorcycle as seen by the driver or car? A. 39 m/s, south B. 9 m/s, north C. 39 m/s, north D. 15 m/s, south
A. 39 m/s, south
An objects hits a wall and bounces back with half of its original speed. What is the ratio of the final kinetic energy to the initial kinetic energy? A. 1/2 B. 4 C. 1/4 D. 2
C. 1/4
A boy throws a rock with an initial velocity of 2.15 m/s at 30.0 degrees above the horizontal. If air resistance is negligible, how long does it take for the rock to reach the maximum height of its trajectory? A. 0.110 s B. 0.194 s C. 0.215 s D. 0.303 s
A. 0.110 s
A ping-pong ball moving east at a speed of 4 m/s, collides with stationary bowling ball. The ping-pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision? A. Neither; both experienced the same magnitude impulse B. the bowling ball C. its impossible to tell since the velocities after the collision are unknown D. the ping pong ball
A. Neither; both experienced the same magnitude impulse
An artillery shell explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion: I. The total momentum of the fragments is equal to the original momentum of the shell II. the total kinetic energy of the fragments is equal to the original kinetic energy of the shell A. Statement I only B. Statement II only C. Both Statement I and II D. Neither statement is true
A. Statement I only
Which of the following statements concerning unit conversion is false? A. Units have no numerical significance, so 1.00 meter=1.00 feet B. Only quantities with the same units can be added or subtracted C. The fact that multiplying an equation by a factor of 1 does not change an equation is important in unit conversion D. units can be treated as algebraic quantities
A. Units have no numerical significance, so 1.00 meter=1.0 feet
You are trying to hit a friend with a water balloon. He is sitting in the window of his dorm room directly across the street (you are at the same height). You aim straight at him and shoot. Just wen you shoot, he falls out of the window! Assuming the balloon has a large enough horizontal velocity component to reach the building, does the water balloon hit hi? A. Yes B. No C. The shot is impossible D. Maybe-- it depends on the speed of the shot
A. Yes
An airplane starts from rest at the end of a runway and begins accelerating. The tires of the plane are rotating with an angular velocity that is uniformly increasing with time. On one of the tires, Point A is located on the part of the tire in contact with the runway surface and point B is located halfway between Point A and the axis of rotation. Which one of the following statements is true concerning this situation? A. both points have the same instantaneous angular velocity B. both points have the same centripetal acceleration C. both points have the same tangential acceleration D. each second, point A turns through a greater angle than point B
A. both points have the same instantaneous angular velocity
Which of the following is FALSE regarding energy? A. energy can be created B. energy is conserved C. energy can be transformed D. energy can be transferred
A. energy can be created
A person sits on a freely spinning lab stool ( no friction ). When the person extends her arms, A. her moment of inertia increases and her angular velocity decreases B. her moment of inertia decreases and her angular velocity decreases C. her moment of inertia decreases and her angular velocity increases D. her moment of inertia increases and her angular velocity increases
A. her moment of inertia increases and her angular velocity decreases
What is the quantity used to measure an objects resistance to changes in rotational motion? A. moment of inertia B. torque C. mass D. angular acceleration
A. moment of inertia
You ride on an elevator that is moving with constant upward acceleration while standing on a bathroom scale. the reading on the scale is A. more than your true weight, mg B. equal to your true weight, mg C.less than your true weight, mg D. could be more or less than your true weight, mg, depending on the magnitude of the acceleration
A. more than your true weight, mg
In which one of the following systems is there a decrease in gravitational potential energy? A. My cat Ozzie jumps down from a bed and lands on his feet B. A child accidentally releases a helium-filled balloon and it flies upward toward the clouds C. My cat Ozzie patiently waits on the floor by his food bowl for dinner D. a truck drives at an average velocity of 25 m/s, due north along a level, country road
A. my cat Ozzie jumps down from a bed and lands on his feet
At student kicks a soccer ball in a high arc (not straight up) toward the opponents goal. At the highest point in its trajectory: A. neither the balls velocity nor its acceleration is zero B. the balls acceleration points upwards C. both velocity and acceleration of the soccer ball are zero D. the balls acceleration is zero but not its velocity
A. neither the balls velocity nor its acceleration is zero
A disk, a hoop, and a solid sphere are released at the top of an inclined plane. They all roll without slipping. In what order do they reach the bottom? A. sphere, disk, hoop B. hoop, disk, sphere C. disk, hoop, sphere D. hoop, sphere, disk
A. sphere, disk, hoop
The centripetal force is best explained by which of the following statements? A. the centripetal force is the net force acting on an orbiting object that maintains it in uniform circular motion B. the centripetal force is a fundamental force of nature C. the centripetal force is the force on an object that is directed radially outward from the center of its orbit D. the centripetal force is the force acting on an orbiting object that is directed along a line that is tangent to the circle
A. the centripetal force is the net force acting on an orbiting object that maintains it in uniform circular motion
What does the word "normal" mean in the phrase "normal force"? A. the component of the force exerted by a surface perpendicular to the surface B. the force is exerted by a surface C. the force is due to contact between two objects D. the component of the force exerted by a surface parallel to thee surface
A. the component of the force exerted by a surface perpendicular to the surface
In which one of the following circumstances does the force do positive work on the object? A. the direction of the force is in the same direction as the objects displacement B. the direction of the force is perpendicular to the objects displacement C. the direction of the force is in the opposite direction to the objects displacement D. No matter the direction of the force, positive work will be done if there is a displacement of the object
A. the direction of the force is in the same direction as the objects displacement
For an object in uniform circular motion, which one of the following statements is false? A. the velocity of the object is constant B. the velocity is directed in a direction that is tangent to the circular path C. the acceleration is direction radially inward D. the magnitude of the acceleration of the object is constant
A. the velocity of the object is cosntant
A stock person at a local grocery store has a job consisting of the following five segments: (1) picking up boxes of tomatoes from the stockroom floor (2) accelerating to a comfortable speed (3) carrying the boxes to the tomato display at constant speed (4) decelerating to a stop (5) lowering the boxes slowly to the floor During which of the five segments of the job does the stock person do positive work on the boxes? A. 1 and 5 B. 1 and 2 C. 1,2,4, and 5 D. 2 and 3
B. 1 and 2
Over the course of a day (24 hours), what is the angular displacement of the seconds hand of the wrist watch in radians? A. 151 rad B. 9050 rad C. 2880 rad D. 1440 rad
B. 9050 rad
Which one of the following statements concerning vectors and scalars is false? A. In calculations, the vector components of a vector may be used in place of the vector itself B. A vector that is zero may have components other than zero C. two vectors are equal only if they have the same magnitude and direction D. a vector component may be either positive or negative
B. A vector that is zero may have components other than zero
Referring to the triangle with sides labeled A, B, and C as shown, which of the following ratios is equal to the cosine of the angle? A. A/B B. B/C C. A/C D. B/A
B. B/C
You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You can either catch the object or deflect the object back towards you friend (such that it moves away from you with the same speed as it was originally thrown). What should you do in order to maximize your speed on the skateboard? A. catch the ball B. deflect the ball C. your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the ball D. there is not enough information given to determine the answer
B. Deflect the ball
Two football players, Ted and Jeff, with the same weight are climbing steps during practice. Ted completes one set of steps in 30 seconds, Jeff completes two sets of steps in 60 seconds. How does the power used by each player compare? A. Jeff uses more power because he does more work B. Jeff and Ted use the same amount of power C. Ted uses less power because his total time is less that Jeff's total time D. Ted uses more power because he only climbs one set of steps while Jeff climbs two sets of steps
B. Jeff and Ted use the same amount of power
A woman is straining to lift a large crate, without success because it is too heavy. We denote the forces on the crate as follows: P is the upward force the woman exerts on the crate, C is the vertical contact force exerted on the crate by the floor, and W is the weight of the crate. How are the magnitudes of these forces related while the woman is trying unsuccessfully to lift the crate? A. P+C<W B. P+C=W C. P+C>W D. P=C
B. P+C=W
Which of the following situations does the object have no acceleration? A. a ball at the end of a string is whirled in a horizontal circle at a constant speed B. an elevator in a tall skyscraper moves upward at a constant speed pf 3 m/s C. Seeing a red traffic light ahead, the driver of a minivan steps on the brake. As a result, the minivan slows from 15 m/s to stop before reaching the light D. a boulder starts from rest and rolls down a mountain
B. an elevator in a tall skyscraper moves upward at a constant speed of 3 m/s
Complete the following statement: When determining the net torque on a rigid body, only the torques due to A. internal forces are considered B. external forces are considered C. interanl and external forces are considered D. forces that form action reaction pairs as in applying newtons third law of motion are considered
B. external forces are considered
A flatbed truck is carrying a crate along a level road. The coefficient of static friction between the load and bed is 0.40. The truck accelerates forward and the crate stays in its place on the truck bed. In what direction is the force that the bed exerts on the crate? A. backward B. forward C. toward the center of the road D. there is no frictional force because the crate does not move with respect to the bed
B. forward
Because Earths orbit is slightly elliptical, Earth actually gets closer to the sun during part of the year. When Ear is closest to the sun its orbital speed is A. the same as when Earth is closest away from the sun B. greater than when Earth is farthest away from the sun C. less than when Earth is closest away from the Sun D. sometimes greater sometimes smaller than when Earth is closest away from the Sun
B. greater than when the Earth is farthest away from the Sun
Which of the following statements most accurately describes the center of gravity of an object? A. it is the point on the object where all of the weight is concentrated B. It is the point from which the torque produced by the weight of the object can be calculated C. It is the point where all the mass is concentrated D. it is the point where gravity acts on the object
B. it is the point from which torque produced by the weight of the object can be calculated
Which one of the following combinations of units is equal to the joule? A. kg*m/s B. kg*m^2/s^2 C. kg*m^2/s D. kg*m^2/s^3
B. kg*m^2/s^2
Suppose you are playing hockey on a new-age ice surface for which there is no friction between the ice and the hockey puck. You wind up and hit the puck as hard as you can. After the puck loses contact with your stick, the puck will A. start to slow down B. not slow down or speed up C. speed up a little, and then slow down D. speed up a little, and then move at a constant speed
B. not slow down or speed up
A block is pulled up an incline with a constant acceleration by a force, P. What is the direction of the kinetic friction force? A. parallel to the incline and in the same direction as P B. parallel to the incline and opposite to P C. perpendicular to the incline D. opposite to P, but not at the same angle as the incline
B. parallel to the incline and opposite to P
A train leaves a station, starting from rest, at time t=0.0s. At time t=3600.0s, the train is traveling due west at 28 m/s. In this example, the 28 m/s is the trains A. displacement B. speed C. acceleration D. velocity
B. speed
A string is attached to the rear-view mirror of a car. A ball is hanging at the other end of the string. The car is driving around in a circle, at a constant speed. Which of the following lists gives all of the forces directly acting on the ball? A. tension B. tension and gravity C. tension, gravity, and the centripetal force D. tension, gravity, the centripetal force, and friction
B. tension and gravity
A child standing at the center of a freely spinning merry go round moves quickly to the outside. Which one of the statements is necessarily true if there is no friction involved and why? A. the angular speed of the system decreases because the moment of inertia has decreased B. the angular speed of the system increases because the moment of inertia of the system has increased C. the angular speed of the system decreases because of the moment of inertia of the system has increased D. The angular speed of the system remains the same because the net torque on the merry go round is zero Nm
B. the angular speed of the system increases because the moment of inertia of the system has increased
A bicycle racer is traveling at constant speed, v, around a circular track. The centripetal acceleration of the bicycle is Ac. What happens to the centripetal acceleration of the bicycle if the speed is doubled to 2v? A. the centripetal acceleration increases to 2ac B. the centripetal acceleration increases to 4ac C. the centripetal acceleration increases to 0.25ac D. the centripetal acceleration does not change
B. the centripetal acceleration increases 4ac
Which one of the following statements concerning kinetic energy is true? A. the kinetic energy of an object is a quantitative measure of its inertia B. the kinetic energy of an object always has a positive value C. the kinetic energy of an object is always equal to the objects potential energy D. the kinetic energy of an object is directly proportional to tis speed
B. the kinetic energy of an object has a positive value
Complete the following statement: If negative work is done on a moving object, A. the velocity of the object will increase B. the kinetic energy of the object will decrease C. the velocity of the object will not change D. the direction of the acceleration of the object will be in the same direction as its displacement
B. the kinetic energy of the object will decrease
The maximum speed at which a car can safely negotiate a frictionless banked curve depends on all of the following except A. the acceleration due to gravity B. the mass of the car C. the angle of banking D. the diameter of the curve
B. the mass of the car
An object is moving forward with a constant velocity. Which statement about this object MUST be true? A. the net force on the object is in the forward direction B. the net force on the object is zero C. no forces are acting on the object D. the acceleration of the object is in the forward direction
B. the net force on the object is zero
Angular momentum cannot be conserved if A. the angular velocity changes B. the net torque is not zero C. the moment of inertia changes D. the angular acceleration changes
B. the net torque is not zero
Complete the following statement: A force that acts on an object is said to be conservative if A. it obeys Newtons laws of motion B. the work it does on the object is independent of the path of motion C. it always acts in the same direction of the motion of the object D. the work it does on the object is equal to the increase in the objects kinetic energy
B. the work it does on the object is independent of the path of the motion
Two private airplanes are taxiing at a small airport. Jim is in plane A rolling due south with respect to the ground. Samantha is in plane B rolling due west with respect to the ground. Samantha is in front of Jim and to his left. In what direction, relative to himself, does Jim see Samantha's plane moving? A. to the south and to the east B. to the north and to the west C. due west D. due east
B. to the north and to the west
A box slides down a frictionless plane inclined at an angle theta above the horizontal. The gravitational force on the box is directed A. parallel to the plane in the same direction as the movement of the box B. vertically C. parallel to the plane in the opposite direction as the movement of the box D. at an angle theta below the inclined plane
B. vertically
Usain Bolt set a world record for the 100.0-m run with a time of 9.58 s. If, after reaching the finish line, Mr.Bolt walked directly back to his starting point in 90.9 s, what is the magnitude of his average speed for the 200.0 m? A. 10.0 m/s B. 1.99 m/s C. 0 m/s D. 5.60 m/s
C. 1.99 m/s
Rank the change in kinetic energy from the largest change to the smallest change: 1. a cars speed changes from 15 m/s to 20 m/s 2. a cars speed changes from 20 m/s to 25 m/s 3. a cars speed changes from 5 m/s to 10 m/s 4. a cars speed changes from 25 m/s to 28 m/s A. 1,2,3,4 B. 3,4,1,2 C. 2,1,4,3 D. 3,1,2,4
C. 2,1,4,3
Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Compare the time it takes each of them to reach the lake below A. Alice reaches the surface of the lake first B. Tom reaches the surface of the lake first C. Alice and Tom will reach the surface at the same time D. none of these
C. Alice and Tom will reach the surface at the same time
Which of the following quantities is defined as the displacement traveled divided by the elapsed time for the travel? A. average speed B. average acceleration C. average velocity D. instantaneous velocity
C. Average velocity
Two children are riding on a merry go round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger linear displacement? A. they have the same non zero linear displacement B. Chid B C. Child A D. They have the same zero linear displacement
C. Child A
Which of the following cannot cause a car to have an acceleration? A. The brakes on the car B. The steering wheel C. The windshield wipers D. both (a) and (b)
C. The windshield
In the dimensional analysis, the dimensions for acceleration are A. [L]^2/[T]^2 B. [L]/[T] C. [L]/[T]^2 D. [L]^2/[T]
C. [L]/[T]^2
The speedometer on a car's dashboard measures which of the following quantities? A. average velocity B. instantaneous velocity C. instantaneous speed D. average speed
C. instantaneous speed
A projectile is launched at a 30 degree angle above the horizontal. Ignore air resistance. The projectile's acceleration is least A. at a point between the launch point and the high point of the trajectory B. at the high point of the trajectory C. misleading question- the acceleration is the same (but nonzero) at all points along the trajectory D. at a point between the high point of the trajectory and where it hits the ground
C. misleading question- the acceleration is the same (but nonzero) at all points along the trajectory
Which of the following statements is true concerning momentum? A. Momentum is a scalar quantity B. momentum is a force C. momentum and impulse are measured in the same units D. momentum is a velocity
C. momentum and impulse are measured in the same units
You drop a package from a plane flying at constant speed in a straight line. Without air resistance, the package will: A. not fall at all B. moved ahead of the plane while falling C. remain vertically under the plane while falling D. quickly lag behind the plane while falling
C. remain vertically under the plane while falling
A ball moves in a circular path on a horizontal, frictionless surface. It is attached to a light string that passes through a hole in the center of the table. If the string is pulled down, thereby reducing the radius of the path of the ball, the speed of the ball is observed to increase. Which one of the following statements provides an explanation for this increase? A. this follows from applying Newtons 3rd law B. When the string is pulled downward, the angular momentum must increase C. The angular momentum of the ball is conserved in this process D. The total mechanical energy of the ball must remain constant because energy is conserved
C. the angular momentum of the ball is conserved in this process
A force is applied to a door knob. This force will be most effective in causing the door to rotate when which of the following is true? A. the lever arm is parallel to the direction of the force B. the lever arm length is zero meters C. the direction of the force is at an angle of 90o with respect to the door D. the lever arm is perpendicular to the door
C. the direction of the force is at an angle of 90o with respect to the door
In which one of the following circumstances does the force do negative work on the object? A. it is not possible to do negative work B. no matter the direction of the force, positive work will be done if there is a displacement of the object C. the direction of the force is the opposite direction to the objects displacement D. the direction of the force is in the same direction as the objects displacement
C. the direction of the force is the opposite direction to the objects displacement
A fireman is slidingn down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the people exert on the fireman. When this force equals the weight of the fireman, what happens? A. the fireman descends with slower and slower speed B. the fireman comes to a stop C. the fireman continues to descend, but with constant speed D. the fireman descends with a smaller acceleration
C. the fireman continues to descend, but with constant speed
Complete the following statement: The center of mass is A. the point at the geometrical center of an object B. the region of an object where most of the mass is located C. the point within an object that moves as if all of the object's mass were located there D. the only point on an object at which the gravitational force acts
C. the point within an object that moves as if all of the objects mass were located there
A rubber ball and lump of putty have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The putty sticks to the wall. Which objects experiences the lessor momentum change? A. both experience the same non zero momentum change B. both experience zero momentum change C. the putty D. the ball
C. the putty
Starting from rest, a particle that is confined to move along a straight line is accelerated at a rate of 5.0 m/s^2. Which statement concerning the slope of the position versus time graph for this particle is true? A. the slope has a constant value of 5.0 m/s B. the slope is not constant decreases with increasing time C. the slope is not constant and increases with increasing time D. the slope has a constant value of 5.0 m/s^2
C. the slope is not constant and increases with increasing time
A collision between two objects is elastic. Which on of the following statements concerning this situation is true? A. the total momentum of the object is zero kg*m/s after the collision B. the vector sum of the velocities of the two objects is equal to zero m/s after the collision C. the total kinetic energy of the object is the same before and after the collision D. the objects stick together and move as one after the collision
C. the total kinetic energy of the objects is the same before and after the collision
Complete the following statement: For a wheel that turns with constant angular speed, A. each point on the rim moves at constant velocity B. the angular displacement of a point on the rim is constant C. the wheel turns through "equal angles in equal times" D. each point on its rim moves with constant acceleration
C. the wheel turns through" equal angles in equal times"
Complete the following statement: The difference between speed and velocity is A. speed has a direction, but velocity does not B. velocity is an average, but speed is always an instantaneous measurement C. velocity has a direction, but speed does not D. speed is an average value, but velocity is always an instantaneous measurement
C. velocity has a direction, but speed does not
Which of the following units is not an SI base unit? A. kilogram B. second C. meter D. mile
D. mile
The spring-loaded gun can launch projectiles at different angles with the same launch speed. At what angle should the projectile be launched in order to travel the greatest distance before landing? A. 60 degrees B. 30 degrees C. 0 degrees D. 45 degrees
D. 45 degrees
A rock is thrown at some angle aboe the horizontal with a certain velocity. It reaches its highest point and starts falling down. What is the velocity of the rock at the highest point of its trajectory? A. 0 B. it is equal to its initial vertical velocity C. 9.8 m/s D. It is equal to its initial horizontal velocity
D. It is equal to its initial horizontal velocity
A packing crate slides down an inclined ramp at constant velocity. Thus we can deduce that A. a net downward force is acting on it B. it is not acted on by appreciable normal force C. a net upward force acting on it D. a frictional force acting on it
D. a frictional force acting on it
What of the following statements concerning vectors and scalars is true? A. In calculations, the vector components of a vector may be used in place of the vector itself B. A scalar component, e.g. A x, must be positive C. Two vectors are equal only if they have the same magnitude and direction D. all of these
D. all of these
Which of the following is true for an object in equilibrium? A. the sum of the horizontal forces is zero B. the sum of the torques is zero C. the sum of vertical forces is zero D. all of these
D. all of these
Which of the following is true for an object in free fall, if we assume +y is in the upward direction? A. the acceleration in the x direction is zero B. the object is not affected by air resistance C. the acceleration in y direction is -9.8 m/s^2 D. all of these
D. all of these
The momentum of an object is dependent on which one of the following quantities? A. acceleration B. mass C. velocity D. both (b) and (c)
D. both (b) and (c)
In an ELASTIC collision between to two objects A. the momentum of the system is conserved but the kinetic energy of the system is not conserved B. the momentum of each object is conserved C. the kinetic energy of each object is conserved D. both the momentum and the kinetic energy of the system are conserved
D. both the momentum and the kinetic energy of the system are conserved
Which of the following quantities is equal to the change in momentum of an object during a collision? A. change in kinetic energy B. net force C. work D. impulse
D. impulse
Two pucks on an air hockey table collide elastically. Complete the following statement: when such a collision occurs in two dimensions, the before and after velocities are best determined by A. using the fact that total kinetic energy is conserved B. making use of the work energy theorem C. using the fact that momentum is conserved and that the initial speeds of the objects must equal the final speeds of the objects D. remembering the momentum is a vector quantity that is conserved in each direction
D. remembering the momentum is a vector quantity that is conserved in each direction
Rolling without slipping depends on A. kinetic friction between the rolling object and the ground B. normal force between the rolling object and the ground C. tension between the rolling object and the ground D. static friction between the rolling object and the ground
D. static friction between the rolling object and the ground
A ball rolls off the edge of a table. The horizontal component of the balls velocity remains constant during its entire trajectory because A. the ball is not acted upon by any force B. the net force acting on the ball is zero C. the ball is not acted upon by a force in the vertical direction D. the ball is not acted upon by a force in the horizontal direction
D. the ball is not acted upon by a force in the horizontal direction
A rock is whirled ont he end of a string in a horizontal circle of radius R with a constant speed v. If the radius of the circle is increased to 3R, while the speed remains v, what happens to the centripetal acceleration of the rock? A. the centripetal acceleration remains the same B. the centripetal acceleration increases by a factor of 9 C. the centripetal acceleration increases by a factor of 3 D. the centripetal acceleration decreases by a factor of 3
D. the centripetal acceleration decreases by a factor of 3
The earth exerts the necessary centripetal force on an orbiting satellite to keep it moving in a circle at constant speed. Which statement best explains why the speed of the satellite does not change although there is a net force exerted on it? A. the acceleration of the satellite is 0 m/s^2 B. the centripetal force has a magnitude mv^2/r C. the centripetal force is canceled by the reaction force D. the centripetal force is always perpendicular to the velocity
D. the centripetal force is always perpendicular to the velocity
Which of the following statements about the moment of inertia is false? A. the moment of inertia depends on the location of the rotation axis relative to the particles that make up the object B. Of the particles that make up an object, the particle with the smallest mass may contribute the greatest amount to the moment of inertia C. the moment of inertia depends on the orientation of the rotation axis relative to the particles that make up the object D. the moment of inertia depends on the angular acceleration of the object as it rotates
D. the moment of inertia depends on the angular acceleration of the object as it rotates
A space shuttle is in orbit around the earth at an altitude of 12,000 miles. Which one of the following statements best explains why the astronauts experience "weightlessness"? A. the pull of the earth on the spaceship is canceled by the pull of the other planets B. the force of the earth on the spaceship and the force of the spaceship on earth cancel because they are equal in magnitude, but opposite in direction C. the centripetal force of the earth on the astronaut is zero newtons D. the spaceship is in free fall; and its floor cannot press upwards on the astronaut
D. the spaceship is in free fall; and its floor cannot press upwards on the astronaut
An object is rolling, so its motion involves both rotation and translation. Which of the following statements must be true concerning this situations? A. the rotational kinetic energy must be constant as the object rolls B. the translational kinetic energy may be 0 joules C. the gravitational potential energy must be changing as the object rolls D. the total mechanical energy is equal to the sum of the translational and rotational kinetic energies and gravitational potential energy of the object
D. the total mechanical energy is equal to the sum of the translational and rotational kinetic energies and gravitational potential energy of the object
A baseball is hit upward and travels along a parabolic arc before it strikes the ground (so air resistance can be neglected). Which of of the following statements is necessarily true? A. the acceleration of the ball decreases as the ball moves upward B. the acceleration of the ball is zero m/s^2 when the ball is at the highest point in the arc C. the velocity of the ball is a maximum when the ball is at the highest point in the arc D. the x-component of the velocity of the ball is the same throughout the ball's flight
D. the x-component of the velocity of the ball is the same throughout the ball's flight
A ladybug sits at rest on a turntable that is rotating with constant angular velocity. During this motion, the ladybugs acceleration vector points A. away from the center of the turntable B. in a direction opposite to the ladybugs motion C. in the direction the ladybug is traveling D. toward the center of the turntable
D. toward the center of the turntable
An automotive test driver travels due north in a prototype hybrid vehicle at 30 mi/h for 2 hours. She the reverses her direction and travels due south at 60 mi/h for 1 hour. What is the average velocity of the vehicle? A. 40 mi/h, north B. 45 mi/h, north C. 40 mi/h, south D. zero mi/h
D. zero mi/h
