Physics Final

An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward at an angle instead, its acceleration will be __ A. 1 g upward B. 1 g downward C. 0 g D. larger than 1 g E. none of these

B. (1 g downward)

Two projectiles are fired from ground level at equal speeds but different angles. One is fired at an angle of 30 degrees and the other at 60 degrees. The projectile to hit the ground first will be the one fired at (neglect air resistance) ___ A. 60 degrees B. 30 degrees C. both hit at the same time

B. (30 degrees)

Two objects of unequal masses, M and m (M > m), are connected by a very light cord passing over an ideal pulley of negligible mass. When released, the system accelerates, and friction is negligible. Which one of the following free-body diagrams most realistically represents the forces acting on the two objects in the moving system? A. M down, m up B. M up and down, m up and down

B. (M up and down, m up and down )

A person is using a rope to lower a 5.0-N bucket into a well with a constant speed of 2.0 m/s. What is the magnitude of the force exerted by the rope on the bucket? A. 0.00 N B. 2.0 N C. 49 N D. 10 N E. 5.0 N

E. (5 N)

A 20-ton truck collides with a 1500-lb car. Which of the following statements must be true? A. During the collision, the force on the truck is smaller than the force on the car B. The car did not slow down during the collision, but the truck did C. During the collision, the force on the truck is smaller than the force on the car D. The truck did not slow down during the collision, but the car did. E. During the collision, the force on the truck is equal to the force on the car

E. (During the collision, the force on the truck is equal to the force on the car)

zero acceleration graph

E. (graph a and b)

In the figure, a 10-lb weight is suspended from two spring scales, each of which has negligible weight. Which one of the following statements about the readings in the scale is true? A. Each scale will read 5 lb. B. Each scale will show a reading between one and 10 lb, such that the sum of the two is 10 lb. However, exact reading cannot be determined without more information. C. The lower scale will read zero, the top scale will read 10 lb. D. The top scale will read zero, the lower scale will read 10 lb. E. None of these is true

E. (none of these is true)

For general projectile motion with no air resistance, the vertical component of a projectile's acceleration ___ A. first decreases and then increases B. is always zero C. continuously decreases D. continuously increases E. remains a non-zero constant

E. (remains a non zero constant)

If a vector's components are all negative, then the magnitude of the vector is negative. T/F

F

If the acceleration of an object is zero, then that object cannot be moving. T/F

F

If the rockets of a spaceship in outer space (far from all gravity) suddenly lose power and go off, the spaceship will gradually slow to a stop. T/F

F

If the velocity of an object is zero, then that object cannot be accelerating. T/F

F

In a collision between a huge SUV and a small hybrid car, the SUV exerts a larger force on the hybrid than the hybrid exerts on the SUV. T/F

F

Inside of a train a ball of weight W is hanging by a light wire at rest from the ceiling. The wire makes an angle X with the ceiling, as shown in the figure. Which one of the following conditions must be true about the tension T in the wire? A. T cos X =W B. T sin X =W C. T=W D. T= ma E. T tan X = W

B. (T sin X =W)

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 second later? A.100 B. 98 C. 50 D. 490 E. none of these

A. (100)

An object is moving with constant non-zero velocity in the +x direction. The velocity versus time group of this object is ___. A. A horizontal straight line B. A vertical straight line C. A straight line making an angle with the time axis. D. A parabolic curve

A. (A horizontal straight line)

Suppose that a car traveling to the east (+x direction) begins to slow down as it approaches a traffic light. Which statements concerning its acceleration must be correct? A. Its acceleration is in the -x direction B. Its acceleration is decreasing in magnitude as the car slows down C. Its acceleration is zero D. The acceleration is in the +x direction

A. (Its acceleration is in the -x direction)

A rock is thrown from the upper edge of a tall cliff at some angle above the horizontal. It reaches its highest point and starts falling down. Which of the following statements about the rock's motion are true just before it hits the ground? A. Its horizontal velocity component is the same as it was just as it was launched. B. Its horizontal velocity component is zero. C. Its speed is the same as it was just as it was launched. D. Its vertical velocity component is the same as it was just as it was launched. E. Its velocity is vertical.

A. (Its horizontal velocity component is the same as it was just as it was launched.)

A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct? A. Its velocity points upward and its acceleration points downward B. Both its velocity and its acceleration points downward C. Its velocity points downward and its acceleration points upward D. Both its velocity and its acceleration point upward

A. (Its velocity points upward and its acceleration points downward)

A pilot drops a package from a plane flying horizontally at a constant speed. Neglect air resistance, when the package hits the ground the horizontal location of the plane will ___ A. be directly over the package B. be behind the package C. depend on the speed of the plane when the package was released D. be in front of the package

A. (be directly over the package)

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will A. be directly over the package. B. be behind the package. C. depend on the speed of the plane when the package was released. D. be in front of the package.

A. (be directly over the package.)

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, the vertical component of velocity __ A. decreases B. remains unchanged C. increases

A. (decreases)

at rest graph A. horizontal line (x vs t) B. parabolic curve C. negative slope D. vertical line E. horizontal line (v vs t)

A. (horizontal straight line w/ x vs t)

Two objects are dropped from a bridge, an interval of 1.0s apart. Air resistance is negligible. During the time that both objects continue to fall, their separation ______ A. increases B. increases at first, but then stays constant C. decreases at first, but then stays constant D. stays constant E. decreases

A. (increases)

For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration ___ A. is always zero B. remains a non-zero constant C. First decreases and then increases D. continuously increases E. continuously decreases

A. (is always zero)

If the velocity versus time graph of an object is a horizontal line, the object is __ A. Moving with zero acceleration B. Moving with constant non-zero acceleration C. At rest D. Moving with increasing speed

A. (moving with zero acceleration)

Two blocks, A and B, are being pulled to the right along a horizontal surface by a horizontal 100 N pull, as shown in the figure. Both of them are moving together at a constant velocity of 2.0 m/s to the right, and both weigh the same. Which of the figures below shows a correct free body diagram of the horizontal forces acting on the upper block, A? A. No horizontal forces on A B. 100 N to the right C. 50 N to the right D. 2, 100 N forces to the right E. !00 N to the right, 100 N to the left

A. (no horizontal forces on A)

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity _____ A. remains a non-zero constant B. continuously decreases C. remains zero D. continuously increases E. first decreases and the increases

A. (remains a non-zero constant)

You are in a train traveling on a horizontal track and notice that a piece of luggage starts to slide directly toward the front of the tracks. From this observation, you can conclude that this train is A. Slowing down B. Slowing down and changing direction C. Speeding up D. Speeding up and changing direction

A. (slowing down)

The slope of a position versus time graph gives__. A. Velocity B. Acceleration C. Displacement D. The distance traveled.

A. (velocity)

From the edge of a roof top you toss a green ball upwards with initial speed V0 and a blue ball downwards with the same initial speed. Air resistance is negligible. When they reach the ground below_____. A. The green ball will be moving faster than the blue ball. B. The two balls will have the same speed. C. The blue ball will be moving faster than the green ball.

B. (the two balls will have the same speed)

Recoil is noticeable if we throw a heavy ball while standing on a skateboard. If instead we go through the throwing motion but hold onto the ball, without friction effects our net recoil will be __ A. small, but noticeable B. zero C. the same as before

B. (zero)

A rock from a volcanic eruption is launched straight up into the air with no appreciable air resistance. Which one of the following statements about this rock while it is in the air is correct? A. On the way up, its acceleration is downward and its velocity is upward, and at the highest point both its velocity and acceleration are zero. B. The acceleration is downward at all points in the motion C. The acceleration is downward at all points in the motion except that is zero at the highest point D. Throughout the motion, the acceleration is downward, and the velocity is always in the same direction as the acceleration.

B. (The acceleration is downward at all points in the motion)

A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the pole exerts on the fireman. When the force on his hands equals his weight, what happens to the fireman? A. The fireman descends with slower and slower speed. B. The fireman continues to descend, but with constant speed. C. The fireman comes to a stop

B. (The fireman continues to descend, but with constant speed.)

Which of the following statements are true about an object in 2-d projectile motion with no air resistance? A. The speed of the object is zero at its highest point B. The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward C. The speed of the object is constant but its velocity is not constant D. The acceleration of the object is +g when the object is rising and -g when it's falling E. The acceleration of th eobject is zero at its highest point

B. (The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward)

In an air chamber, a pebble is thrown horizontally, and tat the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles. A. The thrown pebble hits first B. They hit at the same time C. They dropped pebble hits first D. We cannot tell without knowing which pebble is heavier

B. (They hit at the same time)

While flying horizontally in an airplane, you notice that a string dangling from the overhead luggage compartment hangs at 15 degrees away from the vertical toward the front of the plane. Using this observation, you can conclude that the airplane is A. accelerating forward B. accelerating backward C. no accelerating because the string is at rest D. moving forward E. moving backward

B. (accelerating backward)

Which of the following situations is impossible? A. an object has constant non-zero acceleration and changing velocity B. an object has constant non-zero velocity and changing acceleration C. an object has velocity directed east and acceleration directed east D. an object has velocity directed east and acceleration directed west E. an object has zero velocity but non-zero acceleration

B. (an object has constant non-zero velocity and changing acceleration)

A bullet fired horizontally from a rifle begins to fall ____ A. after air friction reduces its speed B. as soon as it leaves the barrel C. neither of these

B. (as soon as it leaves the barrel.)

A racing car accelerates uniformly from rest along a straight track. This track has markers spaced a equal distances along it from the start, as shown in the figure. The car reaches a speed at 140 km/h as it passes marker 2. Where on the track was the car when it was traveling at half this speed, that is 70 km/h? A. At marker 1 B. Between marker 1 and marker 2 C. Before marker 1

B. (between marker 1 and marker 2)

Mary and Debora stand on a snow-covered roof. They both throw the snowballs with the same initial speed, but in different directions. Mary throws her snowball downward at 30 below the horizontal. Debora throws her snowball upward, at 30 degrees above the horizontal. Which of the following statements are true about just as the snowballs reach the ground below? A) Maryʹs snowball will have a higher speed than Debraʹs. B) Both snowballs will hit the ground with the same speed. C) Maryʹs snowball never hits the ground since it is thrown downwards. D) Debraʹs snowball never hits the ground since it is thrown upwards. E) Debraʹs snowball will have a higher speed than Maryʹs.

B. (both snowballs hit the ground with the same speed)

Two boxes P and Q on a perfectly smooth horizontal surface are connected by a light horizontal card. The mass of P is greater than that on Q. A horizontal force is supplied to box Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P is A. zero B. less than F but not zero C. greater than F D. equal to F

B. (less than F but not zero)

A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory ____ A. both the velocity and the acceleration of the soccer ball are zero B. neither the ball's velocity nor its acceleration are zero C. the ball's velocity points downward D. the ball's acceleration points upward E. the ball's acceleration is zero but its velocity is not zero

B. (neither the ball's velocity nor its acceleration are zero)

A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory A. both the velocity and the acceleration of the soccer ball are zero. B. neither the ball's velocity nor its acceleration are zero. C. the ball's velocity points downward. D. the ball's acceleration points upward. E. the ball's acceleration is zero but its velocity is not zero.

B. (neither the ball's velocity nor its acceleration are zero.)

A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance? A. It is impossible to tell because we do not know their masses B. The stone C. The ball D. Both are traveling at the same speed

B. (the stone)

Which of the following has the largest momentum relative to Earth? A. a dog running down the street B. a tightrope walker crossing Niagara Falls C. a pickup truck speeding along a highway D. A Mack truck parked in a lot

C. (a pickup truck speeding along a highway)

When is the average velocity of an object equal to the instantaneous velocity? A. Only when the velocity is decreasing at a constant rate B. Never C. When the velocity is constant D. Always E. Only when the velocity is increasing at a constant rate

C (When the velocity is constant)

A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is ___ A. 15 m B. 10 m C. 5 m

C. (5 m)

The slope of a velocity versus time graph gives__. A. Displacement B. The distance traveled C. Acceleration D. Velocity

C. (Acceleration)

If the position versus time graph of an object is a horizontal line, the object is ____ A. Moving with constant non-zero speed. B. Moving with constant non-zero acceleration C. At rest D. Moving with increasing speed.

C. (At rest)

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30 degrees below the horizontal; Debra throws her snowball upward, at 30 degrees above the horizontal.Which of the following statements are true about just before the snowballs reach the ground below? A. Both snowballs will take the same amount of time to hit the ground. B. Mary's snowball has a greater downward acceleration than Debra's snowball. C. Debra's snowball will stay in the air longer than Mary's snowball. D. Mary's snowball will stay in the air longer than Debra's snowball.

C. (Debra's snowball will stay in the air longer than Mary's snowball.)

James and John diver from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance. A. Cannot be determine without knowing the mass of both James and John B. James reaches the surface of the lake first C. James and John will reach the surface of the lake at the same time D. Cannot be determined without knowing the weight of both James and John. E. John reaches the surface of the lake first

C. (James and John will reach the surface of the lake at the same time)

James and John dive from an overhand into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance. A. Cannot determine without knowing the mass of both James and John. B. James reaches the surface of the lake first. C. James and John will reach the surface of the lake at the same time. D. Cannot be determined without knowing the weight of both James and John. E. John reaches the surface of the lake first.

C. (James and John will reach the surface of the lake at the same time.)

Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct? A. The acceleration is toward the west B. Since the car is slowing down, its acceleration must be negative C. The acceleration is toward the east D. The acceleration is zero

C. (The acceleration is toward the east)

Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the displacement and the distance traveled by the object. A. This displacement can be either greater than, smaller than, or equal to the distance traveled. B. The displacement is either greater than or equal to the distance traveled. C. The displacement is either less than or equal to the distance traveled. D. The displacement is always equal to the distance traveled

C. (The displacement is either less than or equal to the distance traveled. )

An object is moving with constant non-zero acceleration in the +x direction. The positive versus time graph of this object is ___. A. A horizontal straight line B. A vertical straight line C. A straight line making an angle with the time axis. D. a parabolic curve

C. (a straight line making an angle with the time axis)

You're driving down the highway and a lovebug spatters onto your windshield. Which undergoes the greater change in momentum? A. Your car B. The lovebug C. both the same

C. (both the same)

You're driving down the highway and a lovebug spatters onto your windshield. Which undergoes the greater force of impact? A. Your car B. The lovebug C. both the same

C. (both the same)

You're driving down the highway and a lovebug spatters onto your windshield. Which undergoes the greater impulse? A. Your car B. The lovebug C. both the same

C. (both the same)

A block of mass m sits at rest on a rough inclined ramp that makes an angle X with the horizontal. What must be true about force of static friction f on the block? A. f =mg cosX B. f > mg sin X C. f= mg sin X D. f> mg E. mg cos X

C. (f = mg sin X)

A person who normally weighs 700 N is riding in an elevator that is moving upward but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read? A. 700 N B. more than 700 N C. less than 700 N

C. (less than 700 N)

When a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to different ___ A. forces B. momenta C. masses D. times

C. (masses)

From the same height, you simultaneously drop a lightweight tennis ball and a heavyweight bowling ball. When they hit the floor they have the same ___ A. force B. momentum C. speed D. all of the above E. none of the above

C. (speed)

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance, when they reach the lake below __ A. the splashdown speed of James must be 9.8 m/s larger than that of John B. the splashdown speed of John must be 2 m/s larger than that of James. C. the splashdown speed of John is larger than that of James D. the splashdown speed of James is larger than that of John E. they will both have the same splashdown speed

C. (the splashdown speed of John is larger than that of James)

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance, when they reach the lake below A. the splashdown speed of James must be 9.8 m/s larger than that of John. B. the splashdown speed of John must be 25 m/s larger than that of James. C. the splashdown speed of John is larger than that of James. D. the splashdown speed of James is larger than that of John. E. they will both have the same splashdown speed.

C. (the splashdown speed of John is larger than that of James.)

A ball is moving at 4 m/s and has momentum of 48 kg m/s. What is the mall's mass? A. 48 kg B. 192 kg C. 4 kg D. 12 kg E. none of the above

D. (12 kg)

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30 degrees below the horizontal; Debra throws her snowball upward, at 30 degrees above the horizontal.Which of the following statements are true about just before the snowballs reach the ground below? A. Mary's snowball will have a higher speed than Debra's snowball. B. Both snowballs hit the ground at the same time. C. Debra's snowball will have a higher speed than Mary's snowball. D. Mary's snowball reaches the ground before Debra's snowball.

D. (Mary's snowball reaches the ground before Debra's snowball.)

A car traveling along the highway needs a certain amount of braking force to stop. More braking force is required when the car has __ A. moe momentum B. more mass C. less stopping distance D. all of the above E. none of the above

D. (all of the above)

The force of a falling apple hitting the ground depends upon __ A. the time of contact with the ground B. whether or not the apple bounces C. the speed of the apple just before it hits D. all of the above

D. (all of the above)

The acceleration due to gravity is lower on the Moon than on Earth. Which one of the following statements is true about the mass and weight of an astronaut on the Moon's surface, compared to Earth? A. Both mass and weight are the same B. Mass is less, weigh is the same C. Both mass and weight are less D. Mass is the same, weight is less

D. (mass is the same, weight is less)

The motion of a particle is described in the velocity vs. time graph shown in the figure. (linear w positive slope) Over the nine-second interval shown, we can say that the speed of the particle ______ A. Decreases and then increases B. Remains constant C. Only decreases D. Only increases E. Increases and then decreases

D. (only increases)

A boulder rolls off a very high cliff and experiences no significant air resistance. While it is falling, its trajectory (or flight path) is never truly vertical. T/F

T

Consider a car that travels between points A and B. The car's average speed can be greater than the magnitude of its average velocity, but the magnitude of its average velocity can never be greater than its average speed. T/F

T

Consider a deer that runs from point A to point B. The distance the deer runs can be greater than the magnitude of its displacement, but the magnitude of the displacement can never be greater than the distance it runs. T/F

T