Physics 151

The force of friction between two surfaces can act A) only when the surfaces of relative to each other B) whether or not the surfaces move relative to each other C) even when the surfaces are far apart and not touching D) only over microscopic distances

B) whether or not the surfaces move relative to each other

Use Newton's second law to answer this question: The acceleration of a vertically thrown ball at the top of its path is A)0 B)10 m/s^2 C)between 0 and 10 m/s^2 D)dependent on the initial speed of the ball

B)10 m/s^2

When your mass increases, your weight A)may remain the same B)also increases C)decreases D)transforms to a greater volume

B)also increases

As mass is added to an object which is pushed with a constant force, its acceleration A)increases B)decreases C)remains the same D)quickly reaches 0

B)decreases

For a given force, acceleration and mass are A)directly proportional to each other B)inversely proportional to each other C)not related D)two words for the same concept

B)inversely proportional to each other

A force interaction requires A)one force B)two forces C)an action force D)a reaction force

B)two forces

The speed of a vertically thrown ball at the top of its path is A) 0 B) 10 m/s^2 C) between 0 and 10 m/s^2 D) dependent on the mass of the ball

A) 0

During each second of free fall, the speed of an object A) changes by the same amount B) changes by increasing amounts each second C) remains constant D) doubles each second

A) changes by the same amount

During each second of free fall, the speed of an object A) increases by the same amount B) changes by increasing amounts each second C) remains constant D) doubles each second

A) increases by the same amount

The center of mass of a donut is located a. in the hole b. in material making up the donut c. near the center of gravity d. over a point of support

a. in the hole

When you whirl a tin can in a horizontal circle overhead, the force that holds the can in the circular path acts in a direction a. inward b. outward c. either inward or outward d. parallel to the force of gravity

a. inward

A lead-filled tennis ball and a regular tennis ball are dropped from the top of a tall building. Air drag does affect their motion. The ball that experiences the greater amount of air drag is the A)lead-filled one B)regular one C)neither, for both experience the same amount of air resistance D)no way to say

A)lead-filled one

If a falling object gains 10 m/s every second it falls, its acceleration is A) 10 m/s B) 10 m/s^2 C) directed upward D) steadily increasing

B) 10 m/s^2

If a ball rolls down an inclined plane with an acceleration of 4 m/s^2, after 1 second it has traveled a distance of A) 4m B) 2m C) 16 m D) not enough information provided

B) 2m

You drive to Chicago, a distance of 500 km, at 50 km/hr. At what speed should you return so that your average speed for the round trio is 100 km/hr? A) 150 km/hr B) Not possible to achieve C) 100 km/hr D) 200 km/hr

B) Not possible to achieve

A motorcycle undergoes acceleration when A) the sun of the external forces is zero B) a nonzero net force acts on it C) it is in equilibrium D) all of these

B) a nonzero net force acts on it

An object with a mass of 1 kg on Earth A) has less mass on the Moon B) has the same mass on the Moon C) has more mass on the Moon D) weighs the same everywhere

B) has the same mass on the Moon

A glance at your speedometer will tell your A) average speed B) instantaneous speed C) overall speed D) acceleration

B) instantaneous speed

When we say that 1 kilogram weights 10 N, we mean that A) 1 kg is 10N B) its true at Earth's surface C) its true everywhere D) mass and weight are one and the same

B) its true at Earth's surface

The force of gravity acting on a 2 kg melon is A) 2 kg B) 10 N C) 20 N D) more than 20 N

C) 20 N

If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, its acceleration is A) one half of 4 m/s B) one half of 4 m/s^2 C) 4 m/s^2 D) 10 m/s^2

C) 4 m/s^2

A hummingbird flying at 4km/hr in a crosswind of 3 km/hr is moving over the ground at A) 3 km/hr B) 4 km/hr C) 5 km/hr D) more than 5 km/hr

C) 5 km/hr

When a ball increases in speed by the same amount of time each second, its acceleration A) also increases each second B) decreases each second C) is constant D) fluctuates randomly

C) is constant

The force that propels a heavy truck along a highway is provided by A)gravity B)Newtown's law of motion C)the highway pushing back on the wheels of the truck D)the air drag acting on the truck

C)the highway pushing back on the wheels of the truck

An object in free fall has a speed of 60 m/s. One second later its speed is A) 10 m/s B) 30 m/s C) 60 m/s D) 70 m/s

D) 70 m/s

Whenever one object exerts force on a second object, the second object exerts a force on the first A) that is in the opposite direction B) that is equal in magnitude C) that occurs at the same time D) all of these

D) all of these

The reason a 10 kg rock falls no faster than a 5 kg rock in free fall is that A) the 10 kg rock has greater acceleration B) the 5 kg rock has greater acceleration C) the force of gravity is the same for both D) the force/mass ratio is the same for both

D) the force/mass ratio is the same for both

The force of air friction (air drag) against a falling sack of potatoes A)acts upward B)increases with increasing area C)increases with increasing speed D)all of the above

D)all of the above

When you do 1000 J of work on a car jack and the gravitational potential energy of the car is increased by 300 J, the efficiency of the jack is a. 30% b. 50% c. 70% d. 130%

a. 30%

A space shuttle orbits about 200 km above Earth's surface so as to be above Earth's a. atmosphere b. gravitational field c. both of these d. none fo these

a. atmosphere

A ball launched into the air at 45 degrees to the horizontal initially has a. equal horizontal and vertical components b. components that do not change in flight c. components that affect each other throughout flight d. a greater horizontal component of velocity that vertically

a. equal horizontal and vertical components

When you toss a projectile horizontally, it curves as it falls. It will be an Earth satellite if the curve it makes a. matches the curve of planet earth b. results in a straight line c. spirals our indefinitely d. none of these

a. matches the curve of planet earth

A planet remains in orbit while falling around the sun due to a. tangential velocity b. zero tangential velocity c. acceleration of about 10 m/s^2 d. centrifugal force

a. tangential velocity

A lunar vehicle is tested on Earth at a speed of 10km/h. When it travels at the same speed on the Moon, its momentum is a. the same b. less c. more d. 0

a. the same

A massive truck and a golf cart have a head-on collision with equal amounts of force. The least amount of acceleration occurs for a. the truck b. the cart, if it is initially at rest c. the cart, whether at rest or moving d. neither for they undergo the same acceleration

a. the truck

When the neck of an air-filled balloon is untied and air escapes, the ballon shoots through the air. The force that propels the balloon is provided by the a) surrounding air b) ejected air c) air still in the balloon d) ground beneath the balloon

b) ejected air

If action is a foot kicking a soccer ball, the reaction is an equal force on the a) ball b) foot c) ground d) air drag of motion

b) foot

A boulder falls due to gravity. The reaction to the force on the boulder is a) air resistance b) the boulder pulling up on the Earth c) the boulder being pulled downward by Earth d) all of these

b) the boulder pulling up on the Earth

How much power is required to raise a 200 kg crate a vertical distance of 2 m in a time of 4 s? a. 400 J b. 1000 J c. 1600 J d. 4000 J

b. 1000 J

A cannonball is fired horizontally at 10 m/s from a cliff. Its speed 1 second after being fired is about a. 10 m/s b. 14 m/s c. 16 m/s d. 20 m/s

b. 14 m/s

A torque is a force a. like any other force b. multiplied by a lever arm c. that is fictitious d. that most often points upward

b. multiplied by a lever arm

A car at the top of a vertical cliff has a potential energy of 100 MJ relative to the ground below. It falls over the edge. When it is halfway to the ground, its kinetic energy is a. 25 MJ b. 50 MJ c. about 100 MJ d. more than 100 MJ

b. 50 MJ

The rotational inertia of an object is greater when most of the mass is located a. near the center b. away from the rational axis c. on the rotational axis d. off-center

b. away from the rational axis

Which more accurately describes what happens in the circular spin cycle of a washing machine? a. water is forced away from the clothes b. clothes are forces into a circular path while water is not c. centripetal force acts on the water but not the clothes d. centrifugal force acts on the clothes but not the water

b. clothes are forces into a circular path while water is not

A shoe on an inclined surface barely remains at rest when friction equals the a. weight mg of the show b. component of mg parallel to the surface c. component of mg perpendicular to the surface d. none of the above

b. component of mg parallel to the surface

Horizontal and vertical components of velocity are equal when the resultant projection angle is a. less and 45 degrees b. equal to 45 degrees c. greater than 45 degrees d. vertical

b. equal to 45 degrees

When Nellie Newton hangs by a pair of ropes at difference angles to the vertical, the rope tension is greater in the rope that makes the a. smallest angel to the vertical b. largest angle to the vertical c. depends on the lengths of the ropes d. all of these, to some degree

b. largest angle to the vertical

For round objects rolling down an incline, the fastest objects are generally those with the a. greatest rotational inertia compared with mass b. lowest rotational inertia compared with mass c. most streamlining for reduced air drag d. highest center of gravity

b. lowest rotational inertia compared with mass

A large dog and a small mouse run down the road with the same kinetic energy. The faster moving one is the a. dog b. mouse c. both run at the same speed d. can't be determined

b. mouse

A piece of clay moving with one unit of momentum strikes and sticks to a heavy bowling ball initially at rest. After the clay and the ball ideally move with a combined momentum of a. a little less than one unit b. one unit c. more than one unit d. much less than one unit

b. one unit

Standing still on a skateboard, you catch a ball tossed horizontally at you. The mass of the ball is one-tenth your mass. Compared with the speed of the caught ball, the speed that both you and the caught ball acquire is a. the same b. one-tenth as much c. 10 times as much d. 100 times as much

b. one-tenth as much

When you whirl a tin can in a horizontal circle overhead, the force that the can exerts on the string acts in a direction a. inward b. outward c. either inward or outward d. parallel to the force of gravity

b. outward

When an astronaut in orbit is weightless, he or she is a. beyond earth's gravity b. still in the grips of earth's gravity c. in the grips of interstellar gravity d. none of these

b. still in the grips of earth's gravity

A ball is tossed into a bale of hay and comes to a stop. If instead, it comes to a stop when hitting a sticky wall, the impulse needed to stop it is a. less b. the same c. more d. 0

b. the same

Compared with the momentum of a 200 lb man running 10 mph, the momentum of a 2000 lb car moving 1 mph is a. 0 b. the same c. greater d. less

b. the same

Without air resistance, the time for a vertically tossed ball to return to where it was thrown is a. 10 m/s for every second in the air b. the same as at the time going upward c. less than the time going upward d. more than the time going upward

b. the same as at the time going upward

The angular momentum of a system is conserved a. never b. under some circumstances c. under all conditions d. when angular velocity remains unchanged

b. under some circumstances

When a squid pushes against water, the squid moves forward because the water, a)offers no resistance b)exerts a net backward force c)exerts a net forward force d)has the same density as the fish

c)exerts a net forward force

In an ideal pulley system, a woman lifts an 80 N crate by pulling a rope downward with a force of 20 N. For every 1 m length of rope she pulls downward, the crate rises a. 50 cm b. 45 cm c. 25 cm d. less than 25 cm

c. 25 cm

A model airplane moves twice as fast as another identical model airplane. Compared with the kinetic energy of the slower airplane, the kinetic energy of the faster airplane is a. the same, for level flight b. twice as much c. 4 times as much d. more than 4 times as much

c. 4 times as much

A 1 kg ball has twice the speed as a 2 kg ball. Compared with the 2 kg ball, the 1 kg ball has a. the same kinetic energy b. twice the kinetic energy c. 4 times the kinetic energy d. more than 4 times the kinetic energy

c. 4 times the kinetic energy

An empty truck traveling at 10 km.h has kinetic energy. How much kinetic energy does it have when its speed is doubled? a. the same kinetic energy b. twice the kinetic energy c. 4 times the kinetic energy d. more than 4 times the kinetic energy

c. 4 times the kinetic energy

The normal force that acts on a block of ice that slides on a ramp a. is equal ot mg at all angles b. gets progressively less as the slope of the ramp increases c. becomes greatest wen the ramp is vertical d. none of the above

c. becomes greatest wen the ramp is vertical

When a falling object bounces as it hits the ground a. the impulse on it is greater than for stopping it b. its change in momentum greater than stopping it c. both of these d. none of these

c. both of these

A simple machine cannot multiply a. force b. distance c. energy d. none of these

c. energy

When two children of different weights balance on a seesaw, they each produce a. equal torques c. unequal torques c. equal-magnitude torques in opposite directions d. equal forces

c. equal-magnitude torques in opposite directions

If the sun were half as massive, its pull on Mars would be a. unchanged b. twice c. half d. 4 times as much

c. half

Our sensation of weight a. is due to our sensation of mass b. is due to the force of gravity c. may or may not be due to the force of gravity d. remains constant as long as mass is constant

c. may or may not be due to the force of gravity

The center of gravity of an object a. lies inside the object b. lies outside the object c. may or may not lie inside the object d. is near the center of mass

c. may or may not lie inside the object OR d. is near the center of mass

When an increase in speed doubles the momentum of a moving body, its kinetic energy a. increases, but less than doubles b. doubles c. more than doubles d. depends on factors not stated

c. more than doubles

When you jump vertically, strictly speaking, you cause Earth to a. also move upward with you b. remain stationary c. move downward d. move sideways a bit

c. move downward

A pendulum bob swings to and from. Its kinetic energy and its potential energy relative to the bottom of its swing are numerically equal to each other at a. the bottom b. one quarter the vertical distance between the bottom and the top of the swing c. one half the vertical distance between the bottom and the top of the swing d. the top of the swing

c. one half the vertical distance between the bottom and the top of the swing

Compared to the gravitational field of Earth at its surface, Earth's gravitational field at a distance 3 times as far from the Earth's center is about a. one-third as much b. one-half as much c. one-ninth as much d. zero

c. one-ninth as much

Gravity can be simulated for astronauts in outer space if their habitat a. is very close to Earth b. is in free fall about earth c. rotates d. revolving about Earth

c. rotates

Inhabitants of the International Space Station do not have a a. force of gravity on their bodies b. sufficient mass c. support force d. condition of free fall

c. support force

When work is done twice as quickly, then the power expended is a. half b. the same c. twice d. 4 times as much

c. twice

When you say momentum is conserved, you mean that a. when an impulse acts on an object, its momentum will change b. momentum can be stored c. when external impulses don't occur, a system's momentum remains the same before and after an interaction d. when two objects collide, the mass and velocity of each object will not change

c. when external impulses don't occur, a system's momentum remains the same before and after an interaction

How much work is done on a 200 kg crate that is hoisted 2 m in a time of 4 s? a. 400 J b. 1000 J c. 1600 J d. 4000 J

d. 4000 J

The resultant of a 30 N force and a 40 N force cannot possibly be a. 10 N b. 50 N c. 70 N d. 80 N

d. 80 N

For an object traveling in a circular path, its angular momentum doubles when its a. linear speed doubles and radius remains the same b. radius doubles and its linear speed remains the same c. mass doubles and linear speed and radius remain the same d. all of these

d. all of these

When no air resistance acts on a projectile , its horizontal acceleration is a. g b. at the right angles to g c. centripetal d. zero

d. zero