Physics 1 Exam 2

What is the kinetic energy of a 0.240-kg baseball thrown at 37.5m/s?

168.8 J

A block with a mass of 39.5 kg is pushed with a horizontal force of 150 N. The block moves at a constant speed across a level, rough plane a distance of 4.80 m. (a) What is the work done (in J) by the 150 N force? (b) What is the coefficient of kinetic friction between the block and the plane?

720 J, .387

A rifle with a weight of 25 N fires a 5.3-g bullet with a speed of 210 m/s. (a) Find the recoil speed of the rifle. (b) If a 625-N man holds the rifle firmly against his shoulder, find the recoil speed of the man and rifle.

-0.433 m/s, -0.017 m/s

Calculate the elastic potential energy of a spring with spring constant k = 225 N/m that is compressed by 1.00 ×10^-2m.

-J

A child on a sled with a total mass of 52.0 kg slides down an icy hillside with negligible friction. The sled starts from rest and has a speed of 3.20 m/s at the bottom. What is the height of the hill (in m)?

.522 m

A child and sled with a combined mass of 50.0 kg slide down a frictionless slope. If the sled starts from rest and has a speed of 3.30 m/s at the bottom, what is the height of the hill?

.556 m

A spring with a spring constant of 375 n/m is stretched 0.01 m a released. Mass of the spring is 100 grams. Calculate the velocity of spring

0.61 m/s

A 75.0-kg swimmer dives horizontally off a 465-kg raft initially at rest. If the diver's speed immediately after leaving the raft is 5.00m/s, what is the corresponding raft speed?

0.806m/s

Two objects collide on a frictionless surface. If one had been at rest before the collision, is it possible for: (i) one object to be at rest after the collision? (ii) both objects to be at rest after the collision? 1.(i) only 2.(ii) only 3.both (i) and (ii) 4.neither (i) nor (ii)

1.(i) only

A block of mass 3.40 kg is placed against a horizontal spring of constant k = 895 N/m and pushed so the spring compresses by 0.0500 m. (a) What is the elastic potential energy of the block-spring system (in J)? (b) If the block is now released and the surface is frictionless, calculate the block's speed (in m/s) after leaving the spring.

1.12 J, .811 m/s

A man of mass M = 75 kg and woman of mass m = 55 kg stand facing each other on an ice rink, both wearing ice skates. The woman pushes the man with a horizontal force of F = 85 N in the positive x-direction. Assume the ice is frictionless. A) what is the man's acceleration? B) what is the reaction force acting on the woman? C) calculate the woman's acceleration.

1.13 m/s^2, -85 N, -1.55 m/s^2

Calculate the elastic potential energy of a spring with spring constant k = 225 N/m that is compressed by 1.00 × 10-2m. A) 1.5x10^-4J B) 1.13x10^-4J C) 2.25 J D) 0.113 J

1.13 x 10^-2

Two ropes are attached to a 50kg object. The first rope applies a force of 35 N and the second, 55N. If the two ropes are perpendicular to each other, what is the resultant acceleration of the object?

1.3m/s^2

A mechanic pushes a 3.00 ✕ 103-kg car from rest to a speed of v, doing 4,740 J of work in the process. During this time, the car moves 30.0 m. Neglecting friction between car and road, find v and the horizontal force exerted on the car. (a) the speed v (b) the horizontal force exerted on the car (Enter the magnitude.)

1.778 m/s, 158 N

Alex throws a 0.25-kg rubber ball down onto the floor. The ball's speed just before impact is 4.5m/s, and just after is 2.9m/s. What is the change in the magnitude of the ball's momentum?

1.9 kg.m/s

A race car moving quickly around a track collides with a mosquito, which splatters on the car's windshield. Which object experiences a greater magnitude impact force? 1.Both experience the same force. 2.One cannot tell, you need to know the speeds of the mosquito and the race car. 3.the mosquito 4.the race car

1.Both experience the same force.

The gravitational potential energy of a system 1.depends on the reference configuration for zero potential energy. 2.is always positive. 3.is always negative. 4.is none of these.

1.depends on the reference configuration for zero potential energy.

When you sit in a chair there is necessarily a reaction force to the gravitational force acting on your body. Which of the following best describes this reaction force? 1.the force of gravity you exert on the Earth 2.the force you exert downward on the seat of the chair 3.the normal force exerted by the chair onto you 4.none of these forces

1.the force of gravity you exert on the Earth

You have a piece of clay and a rubber ball, both of the same mass. You want to close a door on the other side of the room by throwing either the clay or the rubber ball at the door. Assume that both would be thrown with the same speed and would impact the door at the same point on the door. With which would you be more likely to cause the door to close further? 1.the rubber ball 2.the clay ball 3.Both would cause the door to close the same distance. 4.It is impossible to tell.

1.the rubber ball

A miniature spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of 7.00g, and the gun and puck have a combined mass of 150g. With the system initially at rest, the radio controlled trigger releases the bullet causing the puck and empty gun to move with a speed of 0.530m/s. What is the bullet's speed?

11.4m/s

Calculate the magnitude of the normal force on a 12.7 kg block in the following circumstances. (Enter your answers in N.) (a) The block is resting on a level surface. (b) The block is resting on a surface tilted up at a 40.8° angle with respect to the horizontal. (c) The block is resting on the floor of an elevator that is accelerating downward at 3.03 m/s2. (d) The block is on a level surface and a force of 105 N is exerted on it at an angle of 40.8° above the horizontal

124.46 N, 94.22 N, 85.98 N, 55.85 N

Popeye, of mass 75.0 kg, has just downed a can of spinach. He accelerates quickly and stops Bluto, of mass 650kg (Bluto is very dense), who is charging in at 15.0m/s. What was Popeye's speed?

130m/s

A Hooke's law spring is compressed 14.6cm from equilibrium, and the potential energy stored is 76.0J. What compression (as measured from equilibrium) would result in 100 J being stored in this case?

16.7 cm

A model train powered by an electric motor accelerates from rest to 0.500 m/s in 30.0 ms. The total mass of the train is 545 g. What is the average power (in W) delivered to the train by the motor during its acceleration?

2.27 W

An elevator weighing 20000N is supported by a steel cable. What is the tension in the cable when the elevator is being accelerated upward at a rate of 3.00m/s2? (g= 9.80 m/s2)

2.6E4 N

A 100-W light bulb is left on for 8.0hours. Over this period of time, how much energy was used by the bulb?

2.6E6 J

An object moves with a constant velocity. Which of the following cannot be true for the object? 1. No forces act on the object. 2.A single force acts on the object. 3.Two forces act on the object. 4.Three forces act on the object.

2.A single force acts on the object.

A model rocket of mass, m, is fired upward from a launch pad with some initial speed, v. A gravitational force is exerted on the rocket 1. at all points in its motion except at it highest point. 2.at all points in its motion. 3.at no points in its motion. 4.at none of these choices.

2.at all points in its motion.

The gravitational force exerted by the Earth on the Moon holds the Moon in an orbit around the Earth. Let us assume that the orbit is perfectly circular. The work done by this gravitational force during a one-week interval in which the Moon moves through a displacement in its orbital path is 1.negative. 2.zero. 3.positive. 4.impossible to determine with the information given.

2.zero.

A pitcher claims he can throw a 0.143-kg baseball with as much momentum as a 2.12-g bullet moving with a speed of 1.50 ✕ 103 m/s. (a) What must the baseball's speed be if the pitcher's claim is valid? (b) Which has greater kinetic energy, the ball or the bullet?

22.24 m/s, The bullet has greater kinetic energy.

At a particular instant, a moving object has a kinetic energy of 254 J and a momentum of magnitude 22.0 kg · m/s. (a) What is the speed (in m/s) of the object at this instant? (b) What is the mass (in kg) of the object at this instant?

23.09 m/s, 0.953 kg

An 8.1 kg object experiences an acceleration of 3.0 m/s^2. (a) What is the magnitude of the resultant force acting on it (in N)? (b) If this same force is applied to a 4.9 kg object, what is the magnitude of the acceleration (in m/s2)?

24.3 N, 4.96 m/s^2

Yuri, a Russian weightlifter, is able tolift 260kg 2.10m in 2.20s. What is his power output?

2432 W

Jerome pitches a baseball of mass 0.300 kg. The ball arrives at home plate with a speed of 40.0m/s and is batted straight back to Jerome with a return speed of 52.0m/s. What is the magnitude of change in the ball's momentum?

27.6 kg.m/s

A 500-N block, on a 30.0°incline, is being held motionless by friction. The coefficient of static friction between the block and the plane is 0.63. The force due to friction is:

272 N

A baseball infielder, mass 78.0kg, jumps up with velocity 3.50m/s and catches a 0.195-kg baseball moving horizontally at 55.0m/s. Of the following, which is closest to the final momentum of the system, infielder and baseball?

273kg.m/s baseball vertical=0

A8.00-kg bowling ball falls from a 3.50-m shelf. Just before hitting the floor, what will be its kinetic energy? (g= 9.80 m/s2and assume air resistance is negligible)

274 J

A 10.0-kg box starts at rest and slides 3.90m down a ramp inclined at an angle of 10°with the horizontal. If there is no friction between the ramp surface and crate, what is the velocity of the crate at the bottom of the ramp? (g= 9.8 m/s2)

3.64 m/s

Find the magnitude of the linear momentum for the following cases. (Enter your answers in kg · m/s.) (a) an electron with mass 9.11 ✕ 10−31 kg, moving with a speed of 4.00 ✕ 106 m/s (b) a 14.0-g bullet moving with a speed of 400 m/s (c) a 77.5-kg athlete running with a speed of 12.5 m/s (d) the Earth (mass = 5.98 ✕ 1024 kg) moving with an orbital speed equal to 2.98 ✕ 104 m/s.

3.64e-24 kg · m/s, 5.6 kg · m/s, 968.75 kg · m/s, 1.78e29 kg · m/s

A watermelon weighs 5.00 lb on Earth. What would it weigh on the Moon, where the free-fall acceleration is one-sixth that on Earth? Give your answer in units of newtons. _________ N What would it weigh on the surface of Pluto, where g is 0.0673 times that on Earth? Give your answer in units of newtons. ________ N What is the mass of the watermelon in kilograms at each of the three locations? Earth- _______________ kg Moon- _____________ kg Pluto- _____________ kg

3.7 N, 1.5 N, 2.27 kg, 2.27 kg, 2.27 kg

A car and a large truck make a head-on collision and stick together. Prior to the collision, the truck's velocity was twice that of the car. Which vehicle experiences the larger change in the magnitude of its momentum? 1.the car 2.the truck 3.Both vehicles experience the same magnitude change in momentum. 4.Impossible to determine.

3.Both vehicles experience the same magnitude change in momentum.

A small sports car collides head-on with a massive truck. Which vehicle experiences the greater impact force (in magnitude)? 1.the car 2.the truck 3.Neither, the force is the same on both.

3.Neither, the force is the same on both.

A ball is thrown straight up in the air. At what position is its kinetic energy a maximum? At what position is the gravitational potential energy of the ball-Earth system a maximum? Consider only the trip up. 1.The maximum kinetic energy occurs at the top of the ball's trajectory and the maximum gravitational potential energy occurs at the top of the ball's trajectory. 2.The maximum kinetic energy occurs at the point of release and the maximum gravitational potential energy occurs at the point of release. 3.The maximum kinetic energy occurs at the point of release and the maximum gravitational potential energy occurs at the top of the ball's trajectory. 4.The maximum kinetic energy occurs at the top of the ball's trajectory and the maximum gravitational potential energy occurs at the point of release.

3.The maximum kinetic energy occurs at the point of release and the maximum gravitational potential energy occurs at the top of the ball's trajectory.

A boulder falls off a cliff toward the ground with no air resistance. The isolated system for which momentum is conserved is 1.only the Earth. 2.only the boulder. 3.both the Earth and the boulder. 4.none of these.

3.both the Earth and the boulder.

A race car moving quickly around a track collides with a mosquito, which splatters on the car's windshield. Which object experiences a greater magnitude acceleration? 1.Both experience the same acceleration. 2.the race car 3.the mosquito 4.One cannot tell, you need to know the speeds of the mosquito and the race car.

3.the mosquito

A horizontal force of 85.0N is applied to move a 46.0-kg cart across a 4.0-m level surface. What work is done by the 85.0-N force?

340 J

A .22-caliber rifle has a 0.470 m long barrel. When fired, a bullet with a mass of 2.50 g accelerates from rest and exits the barrel at a speed of 370 m/s. What is the net force on the bullet (in N) while it is in the barrel? (Enter the magnitude. Assume a constant acceleration.)

364.1 N

An automobile of mass 2500kg moving at 50.0m/s is braked suddenly with a constant braking force of 8500N. How far does the car travel before stopping?

368 m

Elastic potential energy depends on the spring constant and the distance the spring is stretched or compressed. By what factor does the elastic potential energy change if the spring's stretch is doubled?

4

An object accelerates when it experiences a non-zero net force. Which of the following statements is always true? 1.The object moves in the direction of the net force. 2.The object's velocity increases. 3.The object's velocity is in the same direction as its acceleration. 4.The object's acceleration is in the same direction as the net force that acts upon it.

4.The object's acceleration is in the same direction as the net force that acts upon it.

Object 1 has more kinetic energy than Object 2. How do the magnitudes of their momenta compare? 1.p1= p2 2.p1> p2 3.p1≥p2 4.not enough information given to tell

4.not enough information given to tell

Which of the following is (are) conserved in an isolated system? 1.the kinetic energy alone 2.the potential energy alone 3.both the potential energy and the kinetic energy 4.the sum of the kinetic energy and the potential energy

4.the sum of the kinetic energy and the potential energy

The heaviest invertebrate is the giant squid, which is estimated to have a weight of about 0.45 tons spread out over its length of 30 feet. What is its weight in newtons?

4000 N

The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. An astronaut's life support backpack weighs 250 lb on Earth. What does it weigh on the Moon?

41.7 lb

A horizontal force of 89.2 N is applied to a 40.5 kg crate on a rough, level surface. If the crate accelerates at 1.13 m/s2, what is the magnitude of the force of kinetic friction (in N) acting on the crate?

43.4 N

Two forces act on a 8.50-kg object. One of the forces is 14.0N. If the object accelerates at 3.50m/s^2, what is the greatest possible magnitude of the other force?

43.8 N

In 1990 Walter Arfeuille of Belgium lifted a 281.5-kg object through a distance of 17.1 cm using only his teeth. (a) How much work did Arfeuille do on the object? (b) What magnitude force did he exert on the object during the lift, assuming the force was constant?

471.7 J, 2.759 kN

man pulls a sled at a constant velocity across a horizontal snow surface. If a force of 85N is being applied to the sled rope at an angle of 56°to the ground, what is the force of friction between sled and snow?

48 N

A 0.41-kg particle has a speed of 5.0 m/s at point A and kinetic energy of 8.1 J at point B. (a) What is its kinetic energy at A? (b) What is its speed at point B? (c) What is the total work done on the particle as it moves from A to B?

5.125 J, 6.286 m/s, 2.975 J

The figure below shows a motorcycle leaving the end of a ramp with a speed of 33.4 m/s and following the curved path shown. At the peak of the path, a maximum height h above the top of the ramp, the motorcycle's speed is 31.6 m/s. What is the maximum height h? Ignore friction and air resistance. (Enter your answer in m.)

5.97 m

A speed boat requires 85.0kW to move at a constant speed of 14.0m/s. What is the resistive force of the water at this speed?

6071 N

CengageAn astronaut applies a force of 450N to an asteroid, and it accelerates at 7.0m/s^ 2. What is the asteroid's mass?

64 kg.

A bodybuilder lifts a 400 N set of weights from ground level to a position over his head, a vertical distance of 1.65 m. How much work (in J) does the bodybuilder do? Assume the weights are moved at constant speed.

660 J

A woman pulls a cart on the horizontal surface with force 500 N making an an angle 600 to the horizontal through 30 m. Calculate the work done by her.

7500 J

CengageA worker pushes a sled with a force of 38.0N over a level distance of 3.60m. If a frictional force of 16.0N acts on the wheelbarrow in a direction opposite to that of the worker, what net work is done on the wheelbarrow?

79.2 J

A uranium nucleus (mass 238 units) at rest decays into a helium nucleus (mass 4.0 units) and a thorium nucleus (mass 234 units). If the speed of the helium nucleus is 5.5×10^5m/s, what is the speed of the thorium nucleus?

9.4E3m/s

2 Kg and 5 Kg masses are separated by 2-meter distance from their centers. The gravitational force between them is A) 1.67 x10^-10N B) 2.8 N C) 5.0 x10^-20N D) 2.3x10^-10N

A) 1.67 x10^-10N

Calculate work done by a man lifting 100 Kg stone from ground to 20 meters high. Gravity g = 9.8 m/s2 A) 19600 J B) 2000 J C) 5 J D) 5000 J

A) 19600 J

An airboat with mass 3.50 x102Kg, including the passenger, has an engine that produces a net horizontal force of 7.70x102N. Find the acceleration of the airboat in m/s2. A)2.20 B) 26.95 x 10^4 C) 0.45 D) none of the above

A) 2.20

Convert 1kWh to Joules A) 3.60x10^6 J B) 746 J C) 1000 J D) 0.5 J

A) 3.60x10^6 J

The kinetic energy of moving object of mass 25 Kg is 3000 J. Calculate its linear momentum. A) 387.30 Kg.m/s B) 387.30 Joules C) 5000 Kg.m/s D) 120 Kg.m/s

A) 387.30 Kg.m/s

1 horsepower is A) 746 J B) 1000 J C) 500 J D) 1 J

A) 746 J

A stone of mass 100 gram is travelling with constant speed of 135 m/s. Calculates it kinetic energy. A) 911 J B) 911250 J C) 13500 J D) 1823 J

A) 911 J

An object continues to be its state of initial states unless external force is applied on it, which is called A) Newton's first law B) Newton's second law C) Newton's third law D) Newton's gravitational law

A) Newton's first law

An object can move even when no force acts on it. A) true B) false

A) true

In elastic collision both momentum and kinetic energy are conserved A) true B) false

A) true

The elastic potential energy of a stretched or compressed spring is always positive. A) true B) false C) can not say D) all of the above

A) true

The force of gravity is inversely proportional to the square of the distance A) true B) false

A) true

If you press a book flat against a vertical wall with your hand, in what direction is the friction force exerted by the wall on the book? A) upward B) downward C) into the wall D) out from the wall

A) upward

Linear momentum is a A) vector B) scaler C) both D) none of these

A) vector

A car of mass 1000Kg is traveling from 20 m/s to 50 m/s with the application of constant net force. Calculate net work done by this force. A)1.05x10^6J B) 4.5x10^5J C) 2x10^5J D) 3x10^4J

A)1.05x10^6J

The SI unit of force is ___________. A)Newton (N) B) Joules (J) C) Watt (W) D) N.m

A)Newton (N)

The force is a physical quantity which changes or tries to change the states of an object. A)True B)False C) Both D) None of the above

A)True

You have a piece of clay and a rubber ball, both of the same mass. You want to close a door on the other side of the room by throwing either the clay or the rubber ball at the door. Assume that both would be thrown with the same speed and would impact the door at the same point on the door. With which would you be more likely to cause the door to close further? A)the rubber ball B)the clay ball C)Both would cause the door to close the same distance. D)It is impossible to tell

A)the rubber ball

A man of mass M = 75 Kg and a women of mass m = 55 Kg stand facing each other on an ice rink, both wearing ice skates. The women push the man with a horizontal force of F = 85.0 N in the positive direction. Assume that ice is frictionless. What is the man's acceleration? A) 2.5 m/s^2 B) 1.13 m/s^2 C) 5.0 m/s^2 D) 0.5 m/s^2

B) 1.13 m/s^2

A man is pushing box with net force of 125 N along the horizontal direction through 20 meter. Calculate work done by man. A) 6.25 J B) 2500 J C) 0 J D) 0.16 J

B) 2500 J

A football player of mass 120 Kg running with velocity 25 m/s in the football field. What is his momentum? A)30000 Kg.m/s B) 3000 Kg.m/s C) 30000 Joules D) 300000 kg.m/s

B) 3000 Kg.m/s

A man lift 50 Kg box through 55 meter height in 5 seconds. Calculate man's power. A) 5000 W B) 5390 W C) 25 W D) 33.33 W

B) 5390 W

100 N force is applied on the object and it accelerates with 1.5 m/s2. What is its mass? A) 50.5 Kg B) 66.7 Kg C) 100 Kg D) 150 Kg

B) 66.7 Kg

Which has a greater value, a newton of gold on Earth or a newton of gold on the `Moon? A) a newton of gold on earth B) a newton of gold on moon C) both same D) none of the above

B) a newton of gold on moon

If an object isn't moving, no external forces act on it. A) true B) false

B) false

The weakest force in nature is A)nuclear force B) gravitational force C) weak force D) EM force

B) gravitational force

A skater is using very low friction rollerblades. A friend throws a Frisbee at her, on the straight line along which she is coasting. Describe each of the following events as an elastic, an inelastic, or a perfectly inelastic collision between the skater and the Frisbee. (b) She tries to catch the Frisbee, but it bounces off her hands and falls to the ground in front of her. A) elastic B) inelastic C) perfectly inelastic

B) inelastic

A skater is using very low friction rollerblades. A friend throws a Frisbee at her, on the straight line along which she is coasting. Describe each of the following events as an elastic, an inelastic, or a perfectly inelastic collision between the skater and the Frisbee. (c) She catches the Frisbee and immediately throws it back with the same speed (relative to the ground) to her friend. A) elastic B) inelastic C) perfectly inelastic

B) inelastic

The collision between truck and car in road accident is an example of A) elastic collision B) inelastic collision C) perfectly inelastic collision D) all of theabove

B) inelastic collision

It is difficult to move or stop heavy object, which is due to the _________________. A) Force B) inertia C) gravity D) all of the above

B) inertia

A boy standing at one end of a floating raft that is stationary relative to the shore walks to the opposite end of the raft, away from the shore. As a consequence, the raft does which of the following? [Hint: Use conservation of momentum.] A) moves away from the shore B) moves toward the shore C) remains stationary

B) moves toward the shore

Two objects of masses m1 and m2, with m1 < m2, have equal kinetic energy. How do the magnitudes of their momenta compare? A) not enough information given B) p1 < p2 C) p1 = p2 D) p1 > p2

B) p1 < p2

Linear momentum is equal to the product of mass and A) time B) velocity C) time D) acceleration

B) velocity

A women is pulling a cart with her child having total mass 75 Kg along horizontal direction with the application of 300 N force which makes an angle 60 degree from the horizontal axis. Calculate work done by women if she pulls through 25 meters. A) 7500 J B) 4750 J C) 3750 J D) 6450 J

C) 3750 J

The unit of work is A) m/s B) N.m2 C) Joules D) newton

C) Joules

The unit of power is A) Joules B) newton C) Watt D) Watt/s

C) Watt

A skater is using very low friction rollerblades. A friend throws a Frisbee at her, on the straight line along which she is coasting. Describe each of the following events as an elastic, an inelastic, or a perfectly inelastic collision between the skater and the Frisbee. (a) She catches the Frisbee and holds it. A) elastic B) inelastic C) perfectly inelastic

C) perfectly inelastic

A small sports car collides head-on with a massive truck. Which vehicle experiences the greater impact force (in magnitude)? A) car B) truck C) same for both D) all of the above

C) same for both

A car and a large truck traveling at the same speed collide head-on and stick together. Which vehicle experiences the larger change in the magnitude of its momentum? A) impossible to determine B) the car C) the change in magnitude of momentum is the same for both D) the truck

C) the change in magnitude of momentum is the same for both

A crate is sitting in the center of a flatbed truck. As the truck accelerates to the east, the crate moves with it, not sliding on the bed of the truck. In what direction is the friction force exerted by the bed of the truck on the crate? A) to the west B) there is no friction force, because the crate isn't sliding C) to the east

C) to the east

A car and a large truck make a head-on collision and stick together. Prior to the collision, the truck's velocity was twice that of the car. Which vehicle experiences the larger change in the magnitude of its A)the car B)the truck C)Both vehicles experience the same magnitude change in momentum. D)Impossible to determine.

C)Both vehicles experience the same magnitude change in momentum.

A boy standing at one end of a floating raft that is stationary relative to the shore walks to the opposite end of the raft, away from the shore. As a consequence, the raft (Hint: use conservation of momentum.) A)remains stationary. B)moves away from the shore. C)Moves towards shore D)None of the above

C)Moves towards shore

An object of mass 75 Kg is one surface of the earth. Calculate force of gravity of earth on this object. A) 755 N B) 7.7 N C) 10 N D) 735N

D) 735N

The acceleration due to gravity (g) of earth is maximum A) on theMt. Everest B) below the surface C) above the surface D) on the surface

D) on the surface

If you fire a bullet from the gun in east direction, the gun will move in A) north direction B) east direction C) south direction D) west direction

D) west direction

Earth is revolving around the sun so that the gravitational force is perpendicular to the displacement of the earth along the path. The work done by earth to revolve around the sun is A) maximum B) minimum C) 9.8 Joules D) zero

D) zero

Object 1 has more kinetic energy than Object 2. How do the magnitudes of their momenta compare? A)p1= p2 B)p1> p2 C)p1≥ p2 D)not enough information given to tell

D)not enough information given to tell

True or False? No force of gravity acts on an astronaut in an orbiting space station.

False

Which of the following statements are true? (a) An object can move even when no force acts on it.True (b) If an object isn't moving, no external forces act on it.False (c) If a single force acts on an object, the object accelerates.True (d) If an object accelerates, a force is acting on it.True (e) If an object isn't accelerating, no external force is acting on it.False (f) If the net force acting on an object is in the positive x-direction, the object moves only in the positive x-direction.False

True, false, true, true, true, false, false

The figure below shows a fisherman in a canoe on a lake. The fisherman's mass is 78 kg, and the canoe's is 120 kg. The fisherman and canoe are initially at rest when the fisherman throws a package of mass m = 15 kg horizontally to the right with a speed of vi = 4.6 m/s. What is the velocity of the canoe after the package is thrown? Neglect any resistance force from the water. (Give the magnitude in m/s, and select the correct direction from the options given.)

magnitude .348 m/s, direction toward the left

If the momentum of an object is tripled, its kinetic energy will change by what factor?

nine

True or False? At three Earth radii from the center of Earth, the acceleration of gravity is 1/9 its surface value.

true

True or false: The elastic potential energy of a stretched or compressed spring is always positive.

true