exam 1

A large and a small person wish to parachute at equal terminal velocities. The larger person will have to

Larger parachute

A pair of tennis balls fall through the air from a tall building. One of them is filled with lead pellets. The ball to reach the ground first is the

the lead ball

A rocket becomes progressively easier to accelerate as it travels upward from the ground mainly because

the mass of the rocket decreases as fuel is burned.

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.

If experimental findings are not reproducible,

the results are not considered valid

A skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of

0.5g

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

1 second

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?

3.0

A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?

6N

In science, an educated guess is called a

hypothesis.

A kilogram is a measure of an object's

mass

When a falling object has reached its terminal velocity, its acceleration is

zero

An object falls freely from rest on a planet where the acceleration due to gravity is twice as much as it is on Earth. In the first 5 seconds it falls a distance of

250 m.

A horse gallops a distance of 10 kilometers in a time of 30 minutes. It's average speed is

20 km/h.

What horizontally-applied force will accelerate a 400-kg crate at 1 m/s/s across a factory floor against a friction force half its weight?

2400N

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is

10 times as much

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

1000N ?

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

100N

A 1-kg mass at the earth's surface weighs about

10N

A 1-kg rock that weighs 10 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is

10N

A man leans over the edge of a cliff and throws a rock upward at 5 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

10m

A car accelerates at 2 meters per second per second. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30 m/s?

15 seconds

An apple at rest weighs 1 N. The net force on the apple when it is in free fall is

1N

A karate chop delivers a blow of 3000 N to a board that breaks. The force that acts on the hand during this event is

3000N

A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time?

300m

At one instant a heavy object in air is moving upward at 50 meters per second. One second later its speed in meters per second is approximately

40 m/s.

When a woman stands at rest with both feet on a scale, it reads 500 N. When she gently lifts one foot, the scale reads

500N

A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about

50N

If a car increases its velocity from zero to 60 km/h in 10 seconds, its acceleration is

6 km/h/s.

A 10-N falling object encounters 4 N of air resistance. The net force on the object is

6n

A coconut and a feather fall from a tree through the air to the ground below. The amount of air-resistance force is

Greater on the coconut

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

Which of the following is not a vector quantity?

Speed

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about

The Same

The synthesis of a large collection of information that contains well-tested and verified hypotheses about certain aspects of the world is known as a scientific

Theory

A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the

Volkswagen.

The vertical height attained by a basketball player who achieves a hang time of a full 1 s is

about 1.25 m.

If you drop an object, it will accelerate downward at a rate of about 10 meters per second per second. If you instead throw it downwards, its acceleration (in the absence of air resistance) will be

about 10 meters per second per second.

A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds?

about 50 m/s

Hang from a pair of gym rings and the upward support forces of the rings will always

add up to equal your weight.

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

arrow's push against the bowstring.

A skydiver steps from a helicopter and falls for a few seconds until he reaches his terminal velocity. Thereafter, until he opens his parachute, his acceleration

decreases.

A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

directed downward.

The newton is a unit of

force

An object following a straight-line path at constant speed

has zero acceleration.

A bullet is fired straight down from the top of a high cliff. Neglecting air resistance, the approximate acceleration of the bullet in meters per second per second

is about 10

A ball thrown straight upward takes 10 seconds to go up and return to the ground. Because of air resistance, the time taken for the ball just to go up is

less than 5 s.

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

mass

Twelve seconds after starting from rest, an object falling freely will have a speed of

more than 100 m/s.

During the time of the year when the Earth starts moving closer to the sun, the sun

moves toward the Earth, but a smaller distance.

A horse exerts 500 N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because

nevertheless there is still an unbalanced force on the wagon.

Starting from rest, the distance a freely-falling object will fall in 0.5 second is about

none of the above

The maximum acceleration of a car while towing a second car twice its mass, compared to its acceleration with no car in tow, is

one third

Science and technology are

related to one another, but not the same thing.

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is

same

The statement, "There are regions beneath Earth's crust that will always be beyond the reach of scientific investigation," is a

speculation.

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity,

the object accelerates in the direction of the applied force.

The attraction of a person's body toward the Earth is called weight. The reaction to this force is

the person's body pulling on the Earth.

When a rock thrown straight upwards gets to the exact top of its path, its

velocity is zero and its acceleration is about 10 meters per second per second.

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

zero.