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75 terms

Wherever there is an action force, there must be a reaction force which:

is exactly equal in magnitude

An archer shoots an arrow, consider the action force to be exerted by the bowstring against the arrow. the reaction to this force is

the arrows push against the bowstring

a player catches a ball. consider the action force to be the impact of the ball agianst the players glove. the reaction to this force is

the force the glove exerts on the ball

player hits ball with bat. action force is impact of bat against ball. the reaction to this force is

the force that the ball exerts on the bat

a baseball player bats a ball with a force of 1000N. the reaction force that the ball exerts against the bat is

1000N

As a ball falls, the action force is the pull of the earths mass on the ball. the reaction force is the

pull of the balls mass on the earth

arnold and suzie pull very hard on opposite ends of a mass-less rope. the greater force on the rope is exerted by:

both the same

a skydiver falls towards tot earth. the attraction of the earth on the diver pulls him down. what is the reaction to this force

none of these

an automobile and a baby carriage traveling at the same speed collide head on. the impact force is

the same for both

a truck and a volkswagen traveling at the same speed have a head on collision. the vehicle that undergoes the greatest change in acceleration will be the

volkswagen

your friend says the strongest man ever cant exert a 50N punch on a piece of tissue held in midair, you:

agree that it cant be done

a piece of rope is pulled on with 400N of force on each side, what would a spring scale read anywhere along the rope?

400 N

ToF it would be just as hard to shake a bowling ball back and forth on the moon as it is on earth

True

ToF a cars acceleration can be decreasing while its speed increases at the same time

True

ToF if a person weighing 600 N hangs from a trapeze supported by 3 ropes, tension on each rope would be 200 N

True

ToF if a body is traveling with a constant velocity this means there can be no forces acting on it

False

What is true about motion?

all motion is relative

when you look at the speedometer in a moving car you see the cars

instantaneous speed

which of the following could be considered an accelerator of your car

the gas pedal, brake, and steering wheel

the two measurements necessary for calculating average speed are

distance and time

a horse gallops a distance of 10 km in 30 minutes, its average speed is

20 km/h

a car maintains a velocity of 100 km/h for 10 seconds. during this interval its acceleration is

zero

if an object moves with constant acceleration its velocity must

change by the same amount each second

if a car increases its velocity from 0 to 60 km/h in 10 seconds its acceleration is

6 km/h/s

in a car accelerates from rest at 2 meters per second, its speed 3 seconds later will be about

6m/s

a car accelerates at 2 meters per second from rest, how much time is needed to reach speed of 30 m/s

15 seconds

the force required to maintain a rocket ship at constant velocity in force in free space is equal to

zero

what statement made about inertia is true

it would be easier to lift a bowling ball on the mood than on earth, but just as hard to shake back and forth

ToF it would be possible for the acceleration of a body to be decreasing and yet its velocity increasing

True

ToF If a linebacker and a horse jockey jump out of a plane at the same time in the presence of air resistance, the jockey will hit the ground first b/c there will be a smaller force of air resistance on him

False

ToF the reason that bodies fall with same constant acceleration of 10 m/s in absence of air resistance is because the force of gravity is the same on all objects

False b/c w/m ratio is the same

ToF the acceleration of a body falling in the presence of air resistance at terminal velocity is 0 m/s2

True

ToF If a book is lying motionless on a table top the only force acting on it is the weight of the book

False

ToF if a body is not accelerating it must be because there are no forces acting on the body

False

ToF a 10 kg sphere and a 20 kg sphere of the same size are falling in air resistance, the 10 kg sphere will reach terminal velocity first

True

ToF regarding the two falling spheres the 20 kg sphere will have a greater amount of air resistance at terminal velocity

True

ToF a push on a 1 kg brick produces an acceleration, neglecting friction to equally accelerate a 20 kg brick one would have to push 10x harder

False, 20x harder

ToF a rock falling in the presence of air resistance reaches terminal velocity in 10 seconds. the rock will fall a greater distance in the 10th second than in the first second of the fall

True

Which has greater mass a king sized pillow or a car battery

Car battery

a kg is a measure of an objects

mass

an object maintains a constant acceleration unless there is a change in

its mass, the applied force, or the air resistance

your weight is

the gravitational attraction force between you and the earth

a newton is a unit of

force

a rock weighs 30 N on earth a second rock weighs 30 n on the moon which has a greater mass

the one on the moon

an object is propelled along a straight line path by a force. if the net force were doubled the objects acceleration would be

twice as much

an object is propelled along a straight line path in space by a force. if the mass of the object somehow becomes twice as much its acceleration

halves

a 10 N falling object encounters 4 N of air resistance the net force on the object is

6 N

whenever the net force on an object is zero, its acceleration

is zero

a 1 kg mass at the earths surface weighs

10 N

a car has a mass of 1000 kg and accelerates at 2 meters per second. what is the magnitude of the net force exerted on the car?

2000 N

a tow truck exerts a force of 3000 N on a car, accelerating it at 2 meters per second. what is the mass of the car?

15,000 kg

a girl pulls on a 10 kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces what is the wagon's acceleration in meters per second per second

3

a bag of groceries has a mass of 10 kilograms and a weight of

about 100 N

a man weighing 800 N stands at rest on two bathroom scales so his weight is evenly distributed on each scale. each scale reads

400 N

if an object of constant mass experiences a constant net force it will have a constant

acceleration

when a falling has reached its terminal velocity its acceleration is

zero

a light woman and heavy man jump from a plane at the same time and open their same sized parachutes at the sa,e time, which person will get to the state of zero acceleration first?

the light woman

a skydiver who weighs 500 N reaches terminal velocity of 90 km/h the air resistance on the diver is then

500 N

a coconut and a feather fall from a tree to the ground, the amount of air resistance force is

greater on the coconut

a skydiver jumps from a high flying plane, as her velocity of fall increases, her acceleration

decreases

a skydiver steps from a helicopter and falls for a few seconds until reaching terminal velocity. then he opens his parachute and his acceleration:

is zero

a 500 N parachutist opens his chute and experiences an air resistance force of 800 N. the net force on him is

300 N upward

a feather and a coin will have equal accelerations when falling in a vacuum because

the ratio of each object's weight to its mass is the same

the difference between impulse and impact force involves the

time the force acts

it is correct to say that impulse is equal to

the change in momentum

two objects have the same size and shape but one is much heavier. when dropped simultaneously they reach the ground at the same time, but the heavier one has a greater

momentum

a large heavy truck and small carriage roll down a hill. neglecting friction, at the bottom of the hill the carriage will have a greater speed acceleration or momentum?

none of these

in order to catch a ball a baseball player reduces the force of impact on his hand because he

increases the time of impact

by bending your knees when jumping from an elevated position you make the time of impact about 10 times as great. the average force your body experiences is

about 1/10 times as great

padded dashboards in cars are safer in an accident than non padded because it enables an

increased time of impact

a 4 kg ball has a momentum of 12 kg m/s. whats the balls speed?

3 m/s

a ball is moving at 3 m/s and has a momentum of 48 kg m/s. what is the balls mass?

16 kg

a heavy truck and s,all car rolling down a hill are forced to stop in the same amount of time. compared to the force that stops the car the force needed to stop the truck is

greater

a 1000 kg car moving at 10 m/s brakes to stop in 5 seconds. the average braking force is

2,000 N

an astronaut floating in space throws a baseball. if the ball floats away at 20 meters per second the astronaut will

move in the opposite direction but at a lower speed