Physics Exam 1

when dishes remain on the table when you yank the tablecloth beneath them, you're demonstrating...

inertia

compared with a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much...

inertia, volume, and mass

the equilibrium rule states that the vector sum of all forces acting on a...

non-accelerating body is zero, body at rest is zero, body in uniform motion is zero

if you push for an hour against a stationary wall, you do no work...

on the wall

an object is pulled with three forces: one at 20-N to the right, another at 40-N to the right, and the third at 30-N to the left. The net force is...

30-N to the right

an 800-N man stand at rest with his weight evenly distributed on two bathroom scales. the reading on each scale is...

400-N

a girl pushes a cart to the left with a 100-N force. At the same time a boy pushes it to the right with a 50-N force. The net force exerted on the cart is...

50-N to the left

a skydiver who weighs 500-N reaches terminal velocity at 90km/h. the air resistance on the skydiver is...

500-N

in raising a 5000-N piano with a pulley system, for every 1m of rope pulled down, the piano rises .1m. ideally, this means the force needed to lift the piano is...

500N

a free-falling object has a speed of 30m/s at one instant. exactly 2 seconds later its speed will be...

50m/s

a skydiver wimps from a high-flying plane. as her velocity of fall increases, her acceleration...

decreases

when an object falls through the air, as velocity increases the net force...

decreases

when a simple machine multiplies force, it decreases...

distance moved

a given net force propels an object along a straight-line path. if the net force were doubled, its acceleration would...

double

a freight train rolls along a track with considerable momentum. if it rolls at the same speed but has twice as much mass, its momentum is...

doubled

when jean standing on slippery ice catches her leaping dog daisy, the momentum of both jean and daisy after the catch is...

equal to their combined momentum before the catch

whirl a rock at the end of a string and it follows a circular path. if the string breaks, the rock tends at first to...

follow a straight-line path

whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is...

greater with the brick wall

a circus diver drops from a high pole into water far below. when he is half-way down...

his kinetic energy and potential energy is halved, he has gained an amount of kinetic energy equal to half his initial potential energy

when the bottom string is pulled slowly in the heavy-ball-and-strings demonstration, tension...

in the top is due to your pull plus the weight of the ball

a hockey puck slides across a frozen pond. if ice friction and air resistance are neglected, the force needed to keep the puck sliding at constant velocity is...

0-N

a sack of potatoes weighing 200-N falls from an airplane. As the velocity of fall increases, air resistance also increases. when air resistance equals 200-N, the sack's acceleration is...

0m/s^2

the gain in speed each second for a freely-falling object is about...

10m/s

a car moves 4 times as fast as another identical car, compared with the slower car, the faster car has...

16 times the kinetic energy

a shopping cart moves with kinetic energy of 40J. if it moves at twice the speed, its kinetic energy is...

160J

a motor scooter undergoes acceleration when it...

changes direction, gains speed, decreases speed

if an object falls with constant acceleration, the velocity of the object must...

continually change by the same amount each second

when peter tosses an egg against a sagging sheet, the egg doesn't break due to...

d. none of these

a chunk of metal has a mass of 1-kg on Earth. If the same chunk were own the Moon its mass would be...

the same

a 10-kg bricked a 1-kg book are dropped in a vacuum. the acceleration of the 10-kg brick is...

the same as that of the 1-kg book

a karate executed a swift blow and breaks a cement block with her bare hand. the magnitude of the force on her hand is...

the same as the force applied to the block

when you push a crate across a level floor at constant velocity, friction between the crate and the floor is...

the same as your pushing force

when a boxer is moving away from a punch, the force experienced is reduced because...

the time of contact is increased

a given net force propels an object along a straight-line path. if the mass were doubled, its acceleration would...

be half

whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is...

both the same

while driving down the highway a bug spatters onto your windshield. which undergoes the greater change in momentum during the time of contact?

both the same

while driving down the highway a bug spatters onto your windshield. which experiences the greater force of impact?

both the same but with different consequences

a heavy ball hangs by a string, with a second string attached to its bottom. a quick pull on the bottom string breaks the...

bottom string

if a charging rhinoceros has momentum, it must also have...

kinetic energy

an object may have potential energy because of its...

location

compared with falling on a wooden floor, a wine glass may not break when it falls on a carpeted floor because of...

longer time to stop

a kilogram is a measure of an object's...

mass

when a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to differences in...

masses

a mack truck and a mini cooper traveling at the same speed collide head-on. the vehicle to undergo the greatest change in velocity will be the...

mini cooper

a heavy truck and a small truck roll down a hill. neglecting friction, at the bottom of the hill the heavy truck has greater...

momentum

a pulley system can...

multiply a force, change the direction of a force

a heavy rock and a light rock in free fall have the same acceleration because the...

ratio of force to mass is the same

arnold and susie small each pull on opposite ends of a rope in a tug-of-war. the greater force on the rope is exerted by...

same by each

to catch a fast-moving softball with your bare hand, you extend your hand forward just before the catch and then let the ball ride backward with your hand. doing this reduces the catching force because the...

time of catch is increased

if you do work on an object in half the time, your power output is...

twice