PHYS CLICKER QUESTIONS

A ball initially at rest is hit by a club. It is in contact with a club for 6.0*10-3 seconds. Just after the club loses contact with the ball, the ball's velocity is 2.0 m/s. If the ball's mass is 50 g, what is the magnitude of the impulse the club gives to the ball?

0.1 kg m/s

an ideal spring has a spring constant of 15 N/m. how much work must an external force do to stretch the spring from 0.1 m to 0.2 m?

0.225 J

a horizontal external force of 10 N acts on a 4 kg bos that lsides across a surface with constant velocity. what is the coefficient of kinetic friction between the bos and the surface?

0.25

a rock is dropped from a height of 40 m above fround. how long does it take the rock to fall the last 10 m before it hits the ground?

0.38 s

a boy has a mass of 20 kg. he is standing on an icy pond when a friend throws a 2 kg ball at him with horizontal velocity of 8 m/s. if the boy catches the balled, how fast will he be moving?

0.727 m/s

a rock is kicked horizontally at 10 m/s off a cliff. the rock strikes the ground 30 m from teh cliff as shown in the figure. what is the approximaate heigh of the cliff, H?

45 m

A ball is dropped from the top of a 125 m tall tower. how long after it has been released does it hit the ground?

5 s

the free-body diagram of a block being pushed up a rough ramp is best repesented by?

E

You put your book on the bus seat next to you while the bus is parked at the bus stop. When the bus begins to quickly move away from the bus stop, the book slides towards the back of the seat, without anything pushing it. Why?

The accelerating bus is not an inertial reference frame

Suppose you are standing on a bathroom scale while riding in an elevator. For a moment the scale reads 175 lb= 778 N while your actual weight is 155 lbs= 689 N. What is your and the elevator's acceleration?

+1.29 m/s^2

A car has a maximum acceleration of 4.5 m/s^2/. What would be its maximum acceleration while towing a second car twice its mass?

1,5 m/s^2

Two particles of masses 2 g and 6 g are separated by a distance of 6 cm. The distance of their center of mass from the heavier particle is

1.5 cm

a laser emits a series of breif ns (10^-0) pulses of light, one per ms (10^-3s). if each pulse has a power of 10!10 W, what is the energy per pulse?

10 J

A ball initially at rest is hit by a club. It is in contact with a club for 6.0*10-3 seconds. Just after the club loses contact with the ball, the ball's velocity is 2.0 m/s. If the ball's mass is 50 g, what was the magnitude of the average net force acting on the ball while in contact with the club?

16.7 N

a cheerleader lifts his 50 kg partner tree times straight up off the ground a distance of 1.1 m beefore releasing her. how much work does he do lifting her?

1650 J

a crane lifts a 100 kg object to a height of 10 m in 5 s. what is its power output?

1960 W

A ring shaped space station with a radius of 2 km is spinning, so that the speed of the rim is 100 m/s. A 50 kg woman sits on the inside of the rim. What is the magnitude of his apparent weight.

250 N

a force of magnitude 10 N compresses an ideal spring by 4mm. what is the magnitude of the force is needed to stretch the same spring by 12 mm?

30 N

a 750 kg car is travelling horizontally with seed 10 m/s. to triple is speed to 30 m/s, how much net work must be done on the car?

300000 J

A ball (mass 0.40 kg) is initially moving to the left at 40 m/s. After hitting the wall, the ball is moving to the right at 40 m/s. What is the impulse of the ball receives during its collision with the wall?

32 kg m/s to the right

a non-constant force is applied to a 10 kg object over a distance of 2.5 m. how much work does the force do?

35 J

a ball is thrown straight upward with an intial speed of 20 m/s. it returns to its starting position after....

4 s

To cause a 20 kg object to experience and acceleration of 2 m/s^2, the magnitude of the net force that needs to be applied to the object is

40 N

in the figure, a 100 N weight is suspended from two spring sclaes, each of which has negligible weight. What is the reading of the scales?

each scale will read 100 N.

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

equal to its weight

Suppose you are standing on a bathroom scale when you are flying in a jet airplane. For a moment the scale reads more than you actual weight. During that moment, the scale is exerting an upward fore on you that is...

greater than your weight

A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed. The constant horizontal force supplied by the woman....

has the same magnitude as the total force which resists the motion of the box

when an increase in speed triples the kinetic energy of a moving object, the magnitude of its momentum

increases by a factor of squarroot of 3

When you fly a kite, there is a time when you must do (positive) work on the kite.

it is the time when you pull the kite in

your friend asks you to stand oerfectly still holding up a weight bar with weights while he takes a picture. are you doing work during this time?

no

` 50 N magnitude force and a 100 N magnitude force both act on the same object. What is the magnitude of the net force acting on the object?

not enough information is given

Your hands push hon a heavy box to slide it across the floor. The other force of the action/reaction pair is....

the box pushing backward against your hands.

If you push on a friend and he is accelerating away from you, how will the force you exert on your friend compare to the force your friend exerts on you?

the forces are equal in magnitude.

A bowling ball rolls down an alley and hits a bowling pin. Which statement is true about the magnitudes of the forces exerted during the impact?

the magnitudes of the forces that they exert on each other are equal.

Consider a car at rest. We can conclude that the downward gravitational force Earth exerts on the car and the upward contact force the surface of the Earth exerts on the car are equal in magnitude and opposite in direction because...

the net force on the car is zero.

A baseball bat with uniform density is cut at the location of its center of mass as shown in the figure. The piece with the smaller mass after the cut is

the piecec on the left

Suppose an ice skater is moving on the surface of a forzen lake at constant velosity. What is trus about the external forces acting on the skater?

there could be some but they all cancel out.

A child playing with very smooth blocks on a very smooth, horizontal table pushing one of the blocks across the table. After the push, when the child's hand is no longer touching the block, the block continues to move with constant velocity becuase...

there is no net force acting on the block.

Some engineers have suggested that we can simulate gravity in outer space by having a circular rotating space station where persons feel an outward - directed fictitious force due to the rotation of the station. The reason they feel such a force is because

they are accelerating toward the center of space station and the walls of the space station provude the centripteal force, which they expereinece as an apparengt weight

Assume the car is accelerating towards the right and its speed is increasing. A cup of coffee left on the roof is accelerating with the car at the same rate. What is the direction of the frictional force on the cup?

towards the right

two balls of putty of equal mass approach each other from opposite directions with equal speeds. they stick together and come to rest. was momentum conseved?

yes