Physics 1114- Multiple Choice Questions

A person is holding a bag of groceries of mass 5.0 kg at a constant vertical height and moves forward with a displacement of d. Given that d=12 m, what is the work done by the force Fp as shown in figure?

0 J

As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?

1 (F straight up on the right)

A 50-N (weight) crate sits on a horizontal floor where the coefficient of static friction between the crate and the floor is .50. A 20-N force is applied to the crate acting to the right. What is the resulting static friction force acting on the crate?

20 N to the left

A tiger is running in a straight line. If we double both the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?

4

As shown in the figure, fluid fills a container having several sections. At which of the indicated points is the pressure greatest?

All the same

Three cars (car A, car B, and car C) are moving with the same speed and slam on their brakes. The most massive car is car A, and the least massive is car C. If the tires of all three cars have identical coefficients of kinetic friction with the road surface, which car travels the longest distance to skid to a stop?

All the same

A 1-kg ball is released from a height of 6 m, and a 2-kg ball is released from a height of 3 m. Air resistance is negligible as they fall. Which of the following statements about these balls are correct?

As they reach the ground, the 1-kg ball will be moving faster than the 2-kg ball. & Both balls will reach the ground with the same kinetic energy.

Two identical grasshoppers jump into the air with he same initial speed and experience no air resistance. Grasshopper A goes straight up, but grasshopper B goes up at a 66 degree angle above the horizontal. Which of the following statements about these grasshoppers are correct?

At their highest point, both of them have the same amount of mechanical energy & grasshopper B is moving faster than grasshopper A & grasshopper A has more gravitational potential energy than grasshopper B

Two frisky otters slide down frictionless hillsides of the same height but different slopes. The slope of the hill of otter 1 is 30 degrees, while the slope of the hill of otter 2 is 60 degrees. If both start from rest, which otter is moving faster when she reaches the bottom of her hill?

Both otters have the same speed at the bottom

A bullet is fired from a rifle which is much heavier than the bullet. As a result each of them experiences some impulse

Both the bullet and rifle experience the same impulse

Which pulls harder gravitationally, the Earth on the Moon, or the Moon on the Earth? Which accelerates more?

Both the same; Moon

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

Down (into the place)

Which of the following statements are correct for processes involving collisions?

Energy is conserved during collisions & Momentum is conserved during collisions & Kinetic energy is conserved for elastic collisions

For elastic collision

Energy, kinetic energy and momentum are conserved

When a heavy metal block is supported by a cylindrical vertical post of radius R, it exerts a force F on the post. If the diameter of the post is increased to 2R, what force does the block now exert on the post

F

Two small objects, with masses m and M, are originally a distance r apart, and the magnitude of the gravitational force on each one is F. The masses are changed to 2m and 2M, and the distance is changed to 4r. What is the magnitude of the new gravitational force?

F/4

If the sum of the external torques on an object is zero, then the sum of the external forces on it must also be zero

False

If three vectors add to zero, they must all have equal magnitudes.

False

If you swing a bucket of water fast enough in a vertical circle, at the highest point the water does not spill out. This happens because an outward force balances the pull of gravity on the water.

False

In order to get an object moving, you must push harder on it than it pushes back on you.

False

A truck loaded with sand accelerates along a highway. The driving force on the truck remains constant. What happens to the acceleration of the truck if its trailer leaks sand at constant rate through a hole in its bottom?

It increases at a steady rate

Which one of these conditions does a geostationary satellite orbiting the Earth fulfill?

It must orbit above the equator

You slam on the brakes of your car in a panic, and skid a certain distance on a straight level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same conditions?

It would have skidded 4 times farther.

Two men, Joel and Jerry, push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do on the car.

Neither of them does any work.

Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?

The buoyant force is the same in both cases

A golf ball is hit with a golf club. While the ball flies through the air, which forces act on the ball? Neglect air resistance.

The force of gravity acting on the ball

A disk and a hoop of the same mass and radius are released at the same time at the top of an inclined plane. If both are uniform, which one reaches the bottom of the incline last if there is no slipping?

The hoop

A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true?

The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball & The magnitude of the change of the momentum of the 5-kg ball is equal to the magnitude of the change of momentum of the 10-kg ball.

An object is moving with constant non-zero velocity. Which of the following statements about it must be true?

The net force on the object is zero.

An object of mass m rests on a flat table. The earth pulls on this object with a force of magnitude mg. what is the reaction force to this pull?

The object pulling upward on the Earth with force mg

A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is

The same as the momentum change of the heavier fragment.

A stone can slide down one of four different frictionless ramps, as shown in the figure. For which ramp will the speed of the ball be the greatest at the bottom?

The speed of the ball will be the same for all ramps.

If the force on an object is in the negative direction, the work it does on the object must be

The work could be either positive or negative, depending on the direction the object moves.

If you hit a feather with a hammer, which of the two objects will feel a stronger force?

They always feel the same sized force

A lightweight object and a very heavy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionless hill with no air resistance. Which object rises to a greater height?

They both slide to exactly the same height.

An astronaut is a short distance away from her space station without a tether rope. She has a larger wrench. What should she do with the wrench to move toward the space station?

Throw it directly away from the space station

A block is initially moving in a flat smooth surface with an initial speed V1. After taking the ramp, it comes down to the ground level and has a new speed given by V2. Which of the following statements is correct?

V1 < V2 because initially it is at a greater vertical height

Swimmers at a water park have a choice of two frictionless water slides, as shown in the figure. Although both slides drop over the same height h, slide 1 is straight while slide 2 is curved, dropping quickly at first and then leveling out. How does the speed V1 of a swimmer reaching the bottom of slide 1 compare with V2, the speed of a swimmer reaching the end of slide 2 if both start from zero speed?

V1=V2

Halley's comet is the only known short-period comet that is regularly visible to the name eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. It orbits the Sun roughly once every 76 years. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid 2061. It comes very close to the surface of the Sun on its closest approach. Which of the following statements is correct?

at the perihelion it moves the fastest

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

be directly over the package.

The solid dot shown in figure is a pivot point. The board can rotate about the pivot. Which force shown exerts the largest magnitude torque on the broad?:

c

A small boat coasts at constant speed under a bridge. A heavy sack of sand is dropped from the bridge onto the boat. The speed of the boat

decreases

In a game of pool, the white cue ball hits the #5 ball and stops, which ether #5 ball moves away with the same velocity as the cue ball had originally. Both balls have the same mass. This type of collision is

elastic

Consider a brick that is totally immersed in water, with the long edge of the brick vertical. The pressure on the brick is

greater on the bottom of the brick

For uniform circular motion, which of the following statements are correct?

he direction of velocity is always tangential & acceleration is directed toward the center of its circular path

The momentum of an isolated system is conserved

in both elastic and inelastic collisions

An air bubble underwater has the same pressure as that of the surrounding water. As the air bubble rises toward the surface (and its temperature remains constant), the volume of the air bubble

increases

Halley's Comet is in a highly elliptical orbit around the sun. Therefore the orbital speed of Halley's comet while traveling around the sun.

increases as it nears the Sun

When a skier skis down a hill, the normal force exerted on the skier by the hill is

less than the weight of the skier

An egg falls from a bird's nest in a tree and feels no effects due to the air. As it falls,

only its mechanical energy is conserved.

If A + B = C and their magnitudes are given by A + B = C, then the vectors and are oriented

parallel to each other.

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 train. From this observation, you can conclude that this train is

slowing down.

When you throw a pebble straight up with initial speed V, it reaches a maximum height H with no air resistance. At what speed should you throw it up vertically so it will go twice as high?

square root of 2V

Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in front throws a very massive ball toward the back and the person i the back catches it. After the ball is caught, the canoe is

stationary

A rubber ball and a lump of clay 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 clay sticks to the wall. Which one of these objects experiences the greater momentum change?

the ball

A large man and a small boy stand facing each other on frictionless ice. They put their hands together and push against each other so that they move apart. Who moves away with the higher speed?

the boy

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?

the force would be the same in both cases

When a car goes around a circular curve on a horizontal road at constant speed, what force causes it to follow the circular path?

the friction force from the road

Which one of the following statements are true about an object in two-dimensional projectile motion with no air resistance?

the horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant

Two cars are moving with the same momentum. Which care has greater speed?

the lighter car

A merry-go-round spins freely when Diego moves quickly to the center along a radius of the merry-go-round. As he does this, it is true to say that

the moment of inertia of the system decreases and the angular speed increases.

If an object is in equilibrium, which of the following statements is not true?

the object must be at rest

You push on box G that is next to box H, causing both boxes to slide along the floor, as shown in the figure. The reaction force to your push is

the push of box G against you.

If you stood on a planet having a mass four times that of Earth's mass, and a radius two times that of Earth's radius, you would weigh

the same as you do on Earth.

A small piece of stone is attached to a string. By holding the other end of the string, you keep rotating the rock in a uniform circular motion on a horizontal plane. What force causes it to follow this circular path?

the tension from the string

The figure shows scale drawings of two objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the play of the drawing at the mid point?

the wheel

Two satellites orbit the Earth in circular orbits of the same radius. One satellite is twice as massive as the other. Which statement is true about the speeds of these satellites.

they have the same speed

For isolated system:

total energy is always conserved

When is the average velocity of an object equal to the instantaneous velocity?

when the velocity is constant

A liquid is kept in a smaller container that has spherical shape and of radius R. While in this smaller container, the density of the liquid is ρ. The same liquid is now transferred in to a bigger container, which is also a sphere, but of radius 2R. What is the density of the liquid when it is contained inthebiggersphere?

ρ