PHY 100 Final

An acorn falls from a tree. Compare its kinetic energy K, to its potential energy U. A) K increases and U decreases. B) K decreases and U decreases. C) K increases and U increases. D) K decreases and U increases. E) Cannot be determined without knowing the initial height of the acorn.

A) K increases and U decreases

In attempting to pull a 1500 kg car out of a ditch, Al exerts a force of 200 N for 5 s, Bill exerts a force of 500 N for two s, and Clyde exerts a force of 300 N for four seconds. The car does not move at all. Who provided the greatest impulse? A) Al B) Bill C) Al, Bill, and Clyde provide equal, D) indeed zero, impulse. E) Clyde

E) Clyde

The temperature of a 50 g sample of aluminum is raised from 20C to 60C when 440 cal of heat are added. The specific heatcapacity of the aluminum is A. not calculable from this data. B. 0.11 cal/g C C. 15.4 cal/g C D. 0.91 cal/g C E. 0.22 cal/g C

E. 0.22 cal/g C

A quantity which is conserved in the collision of a car and a truck is A. kinetic energy. B. nervous energy. C. momentum of the car. D. momentum of the truck. E. total momentum.

E. total momentum.

A dancer begins performing a pirouette with arms extended. (A pirouette is a complete spin about a vertical axis.) This motion is completed most easily when the rotational inertia is decreased by A) extending the arms and one leg straight out to the sides. B) holding the arms straight up and extending one foot straight out to the side. C) bringing the arms and legs in a line with the body. D) ending at the waist at a right angle.

C) brining her arms and legs in a line with the body L= Iw

A child riding on a swing rises to a height 1.0 m above the lowest point. Another child of equal mass whose speed at the lowest point is twice as great will rise A) to the same height. B) twice as high. C) four times as high. D) to a height which depends on the mass.

C) four times as high.

Car A travels with speed v around curve number one, which has a radius r. Car B travels with speed 2v around curve number two, which has a radius 2r. The acceleration will be A) the same for both cars. B) zero for both cars. C) greater for car B. D) greater for car A.

C) greater for car B.

A ball is whirled on the end of a string in a horizontal circle at constant speed. Suddenly, the string breaks. Immediately after the string breaks, the ball will A) move horizontally inward toward the center of the circle. B) move horizontally outward from the center of the circle. C) have a horizontal velocity that is tangential to the circle. D) drop straight down.

C) have a horizontal velocity that is tangential to the circle.

Two cars are moving around a circular track at the same constant speed. If car 1 is at the inner edge of the track and car 2 is at the outer edge, then A) the accelerations of both cars are equal and greater than zero. B) the acceleration of car 1 is less than the acceleration of car two. C) the acceleration of car 1 is greater than the acceleration of car 2. D) the accelerations of both cars are zero.

C) the acceleration of car 1 is greater than the acceleration of car 2.

A ball at the end of a string is swinging as a simple pendulum. Assuming no loss in energy due to friction, we can say for the ball that A) The potential energy is maximum at the lowest position of the ball. B) the potential energy is maximum where the kinetic energy is maximum. C) the potential energy is maximum where the kinetic energy is a minimum. D) the kinetic energy is maximum at each end of the motion.

C) the potential energy is maximum where the kinetic energy is a minimum

An object with a kinetic energy of 50 J is stopped in a distance of 0.01 m. The average force that stops the object is A) 500 N. B) 50 N. C) 5,000 N. D) 50,000 N. E) 0.5 N

C)5,000 N.

Identify the force of friction involved in the two scenarios. Case 1: A force is applied on a book at rest on a table to slide it across. Case 2: A shopping cart is pushed to keep moving it at constant velocity. A) Case 1 involves kinetic friction, Case 2 involves static friction. B) Case 1 and Case 2 both involve static friction. C) Case 1 involves static friction, Case 2 involves kinetic friction. D) Case 1 and Case 2 both involve kinetic friction.

C)Case 1 involved static friction, Case 2 involves kinetic friction

Which of the following statements is true about friction? A) Static friction is less than kinetic friction. B) Friction acts in the opposite direction of the normal force. C) Friction exists only when an object is in motion. D) Friction always opposes the motion or attempted motion.

C)Friction exists only when an object is in motion

Two students have a "tug-of-war" on a smooth gym floor. One student has a mass of 70 kg and is wearing socks, but no athletic shoes. The other student has a mass of 60 kg and is wearing athletic shoes. The student most likely to win will be: A) the 60 kg student because he can pull harder on the 70 kg student. B) the 70 kg student because he can pull harder on the 60 kg student. C) the 60 kg student because he has greater frictional force. D) the 70 kg student because he has greater frictional force.

C)the 60 kg student because he has greater frictional force

The average force required to accelerate a 0.20-kg ball from rest to 30 m/s in 0.002 s is A. 75,000 N. B. 15,000 N. C. 3,000 N. D. 0.003 N

C. 3,000 N.

Which process does not transfer heat energy between objects? A. Convection. B. Radiation. C. Reflection. D. Conduction.

C. Reflection.

Four samples of steel, lead, alcohol, and glass all have the same mass and are all initially at 20C. After 100 calories of heat are added to each sample, the final temperatures are 38.2C for the steel, 85.6C for the lead, 23.4C for the alcohol, and 30C for the glass. Which of these four materials has the largest specific heat capacity? A. The steel. B. The lead. C. The alcohol. D. The glass. E. All have the same heat capacity, since all absorbed 100 cal of heat.

C. The alcohol.

On a cold winter's morning you awake and step out of bed. One foot is on the tile floor and the other is on a rug on the floor. Which statement is true? A. The tile feels colder because it is smoother than the rug. B. The tile feels colder because it is connected to the cold ground outside. C. The tile feels colder because it conducts heat more rapidly away from your foot. D. The tile feels colder because it cannot absorb water like the rug can.

C. The tile feels colder because it conducts heat more rapidly away from your foot.

Hot cider is poured into a metal cup. Shortly thereafter the handle of the cup becomes hot. This is due to the process of A. radiation. B. convection. C. conduction. D. will remain the same if the work done exceeds the heat added.

C. conduction.

During the course of a demonstration the professor is called away. When he returns he finds a beaker of water that was at room temperature is now at a slightly higher temperature. There is a stirring rod on the desk and a cigarette lighter. The professor can assume that the temperature increase is due to A. heat added to the system. B. mechanical work done on the system. C. either heat added or mechanical work done.

C. either heat added or mechanical work done

An ice cube in a glass of water is pushed to the bottom of the glass and held there with a straw. Consequently, the buoyant force on the ice cube is now A. exactly balanced by the force exerted only by the straw. B. exactly balanced by the weight of the ice cube. C. greater than when the cube was floating at the top. D. the same as when the cube was floating at the top.

C. greater than when the cube was floating at the top.

If you were standing on a cart that was at rest and free to roll (ignore friction) and someone threw a 10 kg ball at you, you would A. not move if you caught the ball because you are more massive than the ball. B. roll backward faster if you caught the ball. C. roll backward faster if the ball bounced off of you elastically. D. roll backward faster if you caught the ball higher above the ground.

C. roll backward faster if the ball bounced off of you elastically.

A clown at the circus blows up a balloon with helium. This balloon will not float to the ceiling unless A. the pressure of the helium inside the balloon is greater than the atmospheric pressure. B. the weight of the balloon is less than the weight of the air displaced by the balloon. C. the balloon and the helium it contains weigh less than the air displaced by the balloon. D. the pressure of the helium inside the balloon is less than the atmospheric pressure.

C. the balloon and the helium it contains weigh less than the air displaced by the balloon.

Two astronauts of equal mass are holding on to each other and moving at a speed of 30 m/s. They push off of each other and one of the astronauts moves in the same direction as the two were initially moving but at 60 m/s. The velocity of the second astronaut is A. 60 m/s backward. B. 30 m/s backward. C. zero. D. 30 m/s forward. E. 60 m/s forward.

C. zero

An object of mass m is held at a vertical height h from ground level. It is then released and falls under the influence of gravity. Which of the following statements is true in this situation? (Neglect air resistance.) A) The total energy of the object is decreasing. B) The kinetic energy of the object is decreasing. C) The potential energy of the object is increasing. D) The total energy of the object is increasing. E) The potential energy of the object is decreasing and the kinetic energy is increasing.

E) The potential energy of the object is decreasing and the kinetic energy is increasing.

A wooden block slides down a rough incline. Which of the following statements is true? A) The total energy of the block is increasing. B) The kinetic energy of the block is decreasing. C) The gravitational potential energy of the block is increasing. D) The total energy of the block is constant. E) The total energy of the block is decreasing.

E) The total energy of the block is decreasing.

Many cars have anti-lock braking system, which prevents the tires from skidding during hard braking and thus stop the car in a shorter distance. How is this possible? A) it uses kinetic friction between the tires and road, which is greater than static friction. B) it uses kinetic friction between the tires and road, which is less than static friction. C) it uses both static and kinetic friction between the tires and road. D) it uses static friction between the tires and road, which is less than kinetic friction. E) it uses static friction between the tires and road, which is greater than kinetic friction.

E) it uses static friction between the tires and road, which is greater than kinetic friction.

If you push twice as hard against a stationary brick wall, the amount of work you do A) quadruples. B) doubles. C) is cut in half. D) remains constant but non-zero. E) remains constant at zero.

E) remains constant at zero.

The amount of heat is often measured in calories. If I add 1 calorie of heat energy to 1 gram of water, the temperature of the water will A. decrease by 1F. B. decrease by 1C. C. stay the same, since water has a very high specific heat. D. increase by 1F. E. increase by 1C.

E. increase by 1C

A balloon inflated with helium is able to float toward the ceiling because A. the weight of the balloon is greater than the weight of the air displaced by the balloon. B. the density of the gas inside the balloon is greater than the density of the atmosphere. C. the pressure of the gas inside the balloon is less than the atmospheric pressure. D. the pressure of the gas inside the balloon is greater than the atmospheric pressure. E. the balloon and the gas it contains weigh less than the air displaced by the balloon.

E. the balloon and the gas it contains weigh less than the air displaced by the balloon.

Which, if either, will produce the greater torque: a force applied at the end of a wrench handle (perpendicular to the handle) or an equal force applied in the same direction near the middle of the handle? Explain. A) The force at the end of the wrench will provide the greater torque because the length of the lever arm associated with that force is greater. B) The force near the middle of the handle will provide the greater torque because the smaller lever arm applies the force closer to the center of rotation. C) The forces will apply the same torque because the forces are equal and are applied in the same direction to the same system.

A) The force at the end of the wrench will provide the greater torque because the length of the lever arm associated with that force is greater.

Three horses are running side-by-side on a merry-go-round: one at the edge, one near the axis, and one in between. Each horse has the same angular speed. Which horse has the greatest linear speed? A) The horse at the edge B) The linear speed is the same for all three horses. C) The horse nearest the axis D) The horse in the middle

A) The horse at the edge V= rw

Using a longer handled wrench to loosen a tight nut allows you to A) apply more torque to the nut. B) pull harder on the wrench. C) exert more force on the nut. D) increase the moment of inertia of the nut.

A) apply more torque to the nut T= r x F

An astronaut weighs 685 N on earth. What would the astronaut's weight be on Jupiter where g = 25.9 m/s2? A) 1810 N B) 17,700 N C) 69.9 N D) 2.70 N

A)1810 N

The average speed of a bicycle is 6 m/s. If a worldclass sprinter can run 100 m in 10 s, can the sprinter move faster than the cyclist? A)Yes B)No C)Not enough information

A)Yes

A ball is thrown up into the air. At the highest point in its trajectory, the net force acting on it is A) equal to its weight. B) greater than its weight. C) less than its weight, but not zero N. D) zero N. E) Cannot be determined without additional information.

A)equal to its weight

As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is A) static friction. B) kinetic friction. C) a combination of static and kinetic friction. D) neither static nor kinetic friction, but some other type of friction. E) It is impossible to tell what type of friction acts in this situation.

A)static friction

You stand on a scale to measure your weight. The reaction to the force the Earth exerts on you is: A) the force you exert on the Earth. B) the force the scales exerts on the Earth. C) the force you exert on the scales. D) the force the scales exert on you. E) the force the Earth exerts on the scales.

A)the force you exert on the Earth

Two bodies have quite different masses, but the net force applied to each of them is the same. The acceleration of: A) the less massive body is larger. B) each body is the same. C) the more massive body is larger

A)the less massive body is larger

While studying for this quiz you realize that you still have 100 g of lukewarm coffee at 40C left in a paper cup. When you pour 20 g of boiling water into the cup, the temperature of the resulting coffee-like mixture will be now A. 50C. B. 60C. C. 67C. D. 70C. E. 80C.

A. 50C

Archimedes' Principle states that... A. an object immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid. B. the pressure of a fluid is inversely proportional to the temperature of the fluid. C. the pressure in a fluid is directly related to the depth below the surface of the fluid. D. the velocity of a fluid is directly proportional to the pressure exerted on the fluid.

A. an object immersed in a fluid is buoyed up by a force equal to the

The purpose of an air bag in an auto is to A. decrease the force applied to you during a collision. B. reduce the impulse on you during a collision. C. make your momentum change occur over a shorter time during a collision. D. reduce your speed just before a collision.

A. decrease the force applied to you during a collision.

Two people sit face to face on nice skateboards that are free to roll without friction. They push each other with a force of 40 N and move apart. Person X, whose mass (including the skateboard) is 50 kg, moves to the left at 3 m/s. Person Z, whose mass (including the skateboard) is 60 kg, A. moves to the right at 2.5 m/s. B. moves to the right at 1 m/s. C. moves to the right at 4 m/s. D. moves to the right at 10 m/s.

A. moves to the right at 2.5 m/s

Three individuals stand with all of their weight on the heel of one foot: a man of weight 600 N and a heel area of 100cm2 , a child of weight 200 N and a heel area of 25 cm2, and woman of weight 450 N and a heel area of 2 cm2. The one exerting the least pressure on the ground is A. the man. B. the child. C. the woman. D. All exert the same

A. the man p= F/A

A box of graham crackers is labeled "120 Calories per serving." Assuming this means 120 kcal, and recalling that 4.16 J = 1 cal, the energy of a serving of the graham crackers is about A. 5 x10^5 J. B. 5 x10^4 J. C. 4.2 x 10^3 J. D. 120 J.

A.5x10^5 J.

A child on a freely rotating merry-go-round moves from near the center to the edge. Will the rotational velocity of the merry-go-round increase, decrease, or not change at all? Explain. A) The rotational velocity must increase to conserve angular momentum because the rotational inertia of the merry-go-round will be less with the child near the edge. B) The rotational velocity must decrease to conserve angular momentum because the rotational inertia of the merry-go-round will be greater with the child near the edge. C) The rotational velocity will not change because there is no change in the mass or the angular momentum of the merry-go-round.

B) The rotational velocity must decrease to conserve angular momentum because the rotational inertia of the merry-go-round will be greater with the child near the edge. V=r x w

An object is moving in a circular path at a constant speed. If the radius of the path is tripled while the speed remains the same, by what factor will the centripetal force on the object be multiplied? A) 9 B) 1/3 C) 1/9 D) 3

B)1/3

A constant net force acts on an object. Describe the motion of the object. A) constant non-zero velocity. B) constant non-zero acceleration. C) increasing acceleration. D) decreasing acceleration. E) zero acceleration.

B)constant non-zero acceleration

Action-reaction forces are: A) equal in magnitude and point in the same direction. B) equal in magnitude and point in opposite directions. C) unequal in magnitude but point in the same direction. D) unequal in magnitude and point in opposite directions.

B)equal in magnitude and point in opposite directions

Which of the following temperatures is the lowest? A. 0C. B. 0F. C. 263 K. D. All are the same.

B. 0F

An 80-kg football player travels to the right at 8 m/s and a 120-kg player on the opposite team travels to the left at 4.0 m/s. The total momentum is A. 240 kg m/s to the left. B. 160 kg m/s to the right. C. zero. D. 160 kg m/s to the left. E. 1120 kg m/s to the right.

B. 160 kg m/s to the right

A hydraulic jack is used to lift a load of weight 4000 N. The load-bearing cylinder has a radius of 4 cm, and the other piston has a radius of 1 cm. What force must be exerted on the smaller piston to support the load? A. 100 N B. 250 N C. 1000 N D. 4000 N E. 16,000 N

B. 250 N F2/F1 = A2/A1 A= pi(r)2

A 3 kg block, initially moving due east at 6 m/s, is acted upon by an impulse having magnitude 6 Ns and direction due west. The final velocity of the block is A. 8 m/s east. B. 4 m/s east. C. 4 m/s west. D. 8 m/s west.

B. 4 m/s east.

It is observed that, as bubbles rise in a deep column of water, the diameter of the bubbles increases. This is best explained by A. Bernoulli's Principle. B. Boyle's Law. C. Archimedes' Principle. D. Pascal's Principle

B. Boyle's Law

Objects A and B are at the same temperature. Object A now has its temperature increased by one Fahrenheit degree, while B has its temperature increased by one Kelvin degree. Which object now has higher temperature? A. Object A. B. Object B. C. Both have the same temperature. D. It is impossible to tell from this data.

B. Object B.

One morning you discover that a tire on your auto is in need of air. As you add air to the tire, which of the following statements is true? A. The density of the air in the tire gets smaller. B. The pressure of the air in the tire increases. C. The number of atoms of air in the tire stays the same. D. All of the statements are true.

B. The pressure of the air in the tire increases.

A sharp knife can more easily cut objects than can a dull knife because A. a greater force can be applied with a sharp knife. B. a greater pressure can be applied with a sharp knife. C. dull knives cannot apply large forces. D. sharp knives have edges that can fit between the molecules of the object.

B. a greater pressure can be applied with a sharp knife.

The lowest possible temperature a body can approach is called A. "mighty" cold. B. absolute zero. C. triple point. D. critical temperature. E. triple absolute zero.

B. absolute zero.

The momentum of a truck is increased by a factor of 2; its weight does not change. Thus, A. its acceleration is doubled. B. its speed doubled. C. its speed increased by a factor of 4. D. its kinetic energy doubled.

B. its speed doubled

A block that has a density of 900 kg/m3 is placed in water (density 1000 kg/m3). The block will A. sink to the bottom. B. sink until it is almost, but not entirely, submerged. C. sink until it is entirely submerged and then remain in place just below the surface. D. sink just a little bit with most of the block above the water. E. rest on the water with none of the block submerged.

B. sink until it is almost, but not entirely, submerged.

If you are launching a matchstick rocket, the action force is the rocket pushing the gases down. What is the reaction force? A. The table pushing the rocket down. B. The gases pushing the rocket up. C. The gases pushing the rocket down.

B.The gases pushing the rocket up

For a 0.1 kg frog to jump to a height of 1.0 meter requires an energy of about A) 0.1 Joule. B) 0.5 Joule. C) 1.0 Joule. D) 10 Joule.

C) 1.0 Joule

1) The armature of a motor is accelerated uniformly from rest to a rotational velocity of 1800 rev/min in 10 seconds. The rotational acceleration of the motor is A) 37.7 rad/s2 B) 90 rad/s2 C) 18.8 rad/s2 D) zero. E) 180 rad/s2

C) 18.8 rad/s2 w0 = 0 w = 1800 rev/min = 1800 x 2p/60 = 188.4 rad/s t = 10 w= w0 + t

Suppose you climb the stairs of a ten-story building, about 30 m high, and your mass is 60 kg. The potential energy you gain is about A) 270 Joule. B) 1800 Joule. C) 18000 Joule. D) 27000 Joule.

C) 18000 Joule.

A body of rotational inertia 1.0 kg m2 is acted upon by a torque of 2.0 Nm. The angular acceleration of the body will be A) 1.0 rad/s2 B) 0.5 rev/s2 C) 2.0 rad/s2 D) 2.0 rev/s2 E) 0.5 rad/s2

C) 2.0 rad/s2 Tnet=I(alpha) 2=1(alpha) alpha= 2 rad/s2

The rotational velocity of a 45 rev/min phonograph record in rad/s is approximately A) 0.75 rad/s. B) 283 rad/s. C) 4.7 rad/s. D) 15.7 rad/s. E) 45 rad/s.

C) 4.7 rad/s. w= 45 rev/min =45 x 2pi/60 =4.71 rad/s

A student plays on a see-saw with her father. The student has a weight of 250 N and is seated 2.4 m from the axis of rotation. Her father balances her when he is seated 0.8 m from the axis. The father's weight is A) 725 N. B) 250 N. C) 750 N. D) 667 N. E) 500 N

C) 750 N.

A figure skater is spinning with her arms extended. She now pulls her arms close to her body. What happens? A) Her angular momentum decreases B) Her rotational inertia increases C) Her rotational inertia decreases D) Her angular momentum increases

C) Her rotational inertia decreases L= Iw

A car travels around a curve with constant speed. The correct statement from the following is A) The car has zero acceleration. B) The car has an acceleration directed outward from the center of the curve. C) The car has an acceleration directed inward toward the center of the curve. D) The car has an acceleration directed in the instantaneous direction of the velocity. E) The velocity of the car is constant.

C) The car has an acceleration directed inward toward the center of the curve.

A quarterback of mass 85 kg is running at 10 m/s. Also, a tackle of mass 100 kg is running at 9 m/s. A) The tackle has the greater kinetic energy. B) The quarterback and the tackle have equal kinetic energies. C) The quarterback has the greater kinetic energy

C) The quarterback has the greater kinetic energy

Virgil rides a skateboard (combined mass 100 kg) at 4 m/s, and Jill rides a bicycle (combined mass 64 kg) at 5 m/s. A) Jill has the greater kinetic energy. B) Virgil has the greater kinetic energy. C) Virgil and Jill have equal kinetic energies.

C) Virgil and Jill have equal kinetic energies.

Jim exerts a force of 500 N against a 100 kg desk that does not move. Virgil exerts a force of 400 N against a 60 kg desk that moves 2 m in the direction of the push. Mik exerts a force of 200 N against a 50 kg desk that moves 4 m in the direction of the push. The most work is done by A) Jim. B) Virgil. C) Virgil and Mik, who do equal amounts of work. D) Mik.

C) Virgil and Mik, who do equal amounts of work.

Describe the energy of a car driving up a hill. A) entirely kinetic B) entirely potential C) both kinetic and potential D) gravitational E) elastic

C) both kinetic and potential

In which of the following cases the car is not accelerating? A) The car travels at a constant speed on a straight road B) The car slows down to a stop C) The car speeds up from rest D) The car slows down while going around a turn

A) The car travels at a constant speed on a straight road

If you are travelling with average speed of 25 m/s, how long will you take to travel 700 m? A)25 s B)28 s C)25 min D)2.8 s

B)28 s Avg Speed = distance/time 25= 700/t t=28s

Work is not being done on an object unless the A) speed is constant. B) net force on the object is zero. C) object is being accelerated. D) object is moving

D) object is moving

The two balls start at the same height as shown. One is dropped from rest while a second is fired horizontally with a speed v. Which one hits the ground first? 1. Red Ball 2. Yellow Ball 3. Both hit at the same time 4. Depends on the mass of the ball

3.Both hit at the same time

A ball is dropped with a speed of 14 m/s from a building 12 m high. What is the acceleration of the ball when it is 6 m from the ground? 1. Greater than 9.81 m/s2 2. Less than 9.81 m/s2 3. Exactly 9.81 m/s2

3.Exactly 9.81 m/s2

A ball is tossed up in the air, it reaches the maximum height and starts falling downward. At the maximum height the ball is momentarily at rest. The acceleration of the ball at that height is: 1. 0 m/s2 2. Greater than 9.8 m/s2 3. Exactly 9.8 m/s2 4. Less than 9.8 m/s2

3.Exactly 9.8m/s2

If a bird feather and a bowling ball are dropped from a certain height at the same time, which of the following is true: 1) The feather will hit the ground first. 2) The bowling ball will hit the ground first. 3) Both will hit the ground at the same time.

3)Both will hit the ground at the same time

Which of the following statement is correct as the ball moves upward? 1)It's acceleration is decreasing 2)Both, it's speed and acceleration are decreasing 3)Its speed is decreasing, but its acceleration remains constant

3)Its speed is decreasing, but its acceleration remains constant

Which of the following statement is correct as the object falls towards the ground? 1)It's acceleration is increasing 2)Both, it's speed and acceleration are increasing 3)Its speed is increasing, but its acceleration remains constant

3)Its speed is increasing, but its acceleration remains constant

Which has the greater kinetic energy? A) A 1 ton car moving at 30 m/s, B) A a half-ton car moving at 60 m/s C) A 1 ton car D) both have same kinetic energy E) a half-ton car

B) A a half-ton car moving at 60 m/s

In using a long steel rod as a lever to move a large rock, where should the fulcrum be placed? A) Anywhere in between - it makes no difference. B) Close to the rock. C) Close to the point where the force is applied. D) Halfway between the rock and the applied force.

B) Close to the rock.

The coefficient of static friction for ice on ice is 0.1, while the coefficient of kinetic friction for ice on ice is 0.03. Based on this information which of these statements is correct? A) The force required to overcome kinetic friction is equal to the force required to overcome static friction. B) The force required to overcome kinetic friction is less than the force required to overcome static friction. C) The force required to overcome kinetic friction is zero. D) The force required to overcome kinetic friction is more than the force required to overcome static friction.

B) The force required to overcome kinetic friction is less than the force required to overcome static friction.

During a softball game, a player running from second base to third base reaches a speed of 4.5 m/s before she starts to slide into third base. When she reaches third base 1.3 s after beginning her slide, her speed is reduced to 0.6 m/s. The players acceleration during the slide is: A) 4 m/s. B)-2 m/s2 C) 3 m/s D) -3 m/s2

D) -3m/s2 Acceleration= (0.6-4.5)/1.3=-3

In a head-on automobile collision, a person's momentum could be reduced from 2000 kg m/s to zero in just 0.1 s. If this occurs, the average force exerted to stop the person is A) 200 N. B) 2,000 N. C) Can't answer without knowing the person's mass. D) 20,000 N.

D) 20,000 N.

A car rounds a curve while maintaining constant speed. The correct statement is: A) The velocity of the car is zero. B) No net force acts on the car. C) The acceleration of the car is zero. D) A net force acts upon the car. The velocity of the car is constant.

D) A net force acts upon the car. The velocity of the car is constant.

An ice skater is in fast spin with her arms held tightly to her body. When she extends her arms, which of the following statement is not true? A)She decreases her angular speed. B) She increases her moment of inertia. C)Her total angular momentum remains constant. D)Her moment of inertia remains constant.

D) Her moment of inertia remains constant L=Iw

A brick slides down a smooth frictionless incline. What happened to the potential energy of the brick? A) It was simply destroyed in the process of sliding. B) Nothing, it is still in the brick but is now called kinetic energy. C) It was converted to other energy forms, mostly heat. D) It was converted to kinetic energy.

D) It was converted to kinetic energy.

Suppose one's hand exerts a force of 12 N upward on a book weighing 10 N. The reaction to the force of the hand on the book is a force of: A) 10 N exerted by the book on the Earth. B) 10 N exerted by the book on the hand. C) 10 N exerted by the Earth on the book. D) 12 N exerted by the book on the hand. E) 2 N exerted by the book on the hand.

D)12N exerted by the book on the hand

The coefficient of static friction between a block and a horizontal floor is 0.40, while the coefficient of kinetic friction is 0.15. The mass of the block is 5.0 kg. If a horizontal force is slowly increased until it is barely enough to make the block start moving, what is the net force on the block the instant that it starts to slide? A) 12 N B) 35 N C) 49 N D) 20 N

D)20 N

A big defensive lineman picks up a fumbled football and begins rumbling toward the end zone. His mass is 150 kg, and his velocity is 6.0 m/s, west. A brave wide receiver, whose mass is 90 kg, must stop that lineman and he is right in the lineman's path, so it has to be a head-on collision. How fast must the wide receiver be running if he wants to drop the lineman in his tracks and save the day? A. 88 mph B. 0.60 m/s C. 8.3 m/s D. 10 m/s

D. 10 m/s

A bullet of mass 0.010 kg and speed of 200 m/s is brought to rest in a wooden block after penetrating a distance of 0.10 m. This process takes 0.02 second. The magnitude of the impulse delivered to the bullet by the block during this time is A. zero. B. 0.98 N. C. 1.0 Ns. D. 2.0 Ns. E. 4.0 Ns.

D. 2.0 Ns

A gas originally occupies a volume of 0.5 m3 at a pressure of 100 kPa. It is slowly allowed to expand until the volume is 2.5 m3. Assuming the temperature is kept constant, the final pressure will be A. 500 kPa. B. 100 kPa. C. 50 kPa. D. 20 kPa. E. 10 kPa.

D. 20 kPa P1V1= P2V2

The temperature of 100 g of water is to be raised from 10C to 90C. The energy needed to do this is about A. 1 x 10^3 cal. B. 5 x 10^3 cal. C. 6 x 10^3 cal. D. 8 x 10^3 cal. E. 5.4 x 10^4 cal.

D. 8 x 10^3 cal.

An iceberg is floating in the ocean with 10% of its volume extending above the ocean's surface. What can you say about the iceberg? A. Its weight is less than the water it displaces. B. It displaces only 90% of its weight in water. C. As it melts, a smaller fraction of its volume will extend above the surface. D. Its density is close to but smaller than the density of water

D. Its density is close to but smaller than the density of water

Water freezes at 273 on the ________ scale. A. Fahrenheit B. Celsius C. Rankin D. Kelvin E. Vernier

D. Kelvin

Force F, acting for time T and over a distance D, gives impulse I. To get the same impulse using half the force, it would be necessary for the force to act A. over a distance 2D. B. over a distance 4D. C. over half the distance D. D. for a time 2T. E. for half the time T.

D. for a time 2T.

On a cold day, a metal fence post feels colder to the touch than a tree. This sensation of different temperatures is explained by the fact that A. the temperature of the tree is higher. B. the specific heat capacity of the metal is higher. C. the specific heat capacity of the wood in the tree is higher. D. the thermal conductivity of the metal is higher. E. the thermal conductivity of the wood in the tree is higher.

D. the thermal conductivity of the metal is higher