Science exam

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

0

Two identical freight cars roll without friction towards each other on a level track. One car rolls at 2 m/s and the other car rolls at 1 m/s. After the cars collide, they couple and roll together with a speed of

0.5 m/s

The mass of a pet turtle that weighs 10N is about

1 kg

A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

400

A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope?

400

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

The persons body pulling on the earth

When you stand at rest on a pair of bathroom scales, the readings on the scales will always

add to equal your weight

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

add up to equal your weight

Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on an isolated piece of tissue paper with his best punch. You

agree that it can't be done.

A force is a vector quantity because it has both

magnitude and direction

The force exerted on the tires of a car to directly accelerate it along a road is exerted by the

road

An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater mass?

the one on the moon

A push on a 1 kg brick accelerates the brick. Neglecting friction, to equally accelerate a 10 kg brick, one would have to push with

10 times as much force

A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is

300 N upward

A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is

3000

A person is attracted toward the center of Earth by a 500-N gravitational force. The Earth is attracted toward the person with a force of

500 N

A 30-kg girl and a 25-kg boy face each other on friction-free roller blades. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girl's speed is

8.3 m/s

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

arrow's push against the bowstring

It is correct to say that impulse is equal to

change in momentum

Compared with the force that brings a small car to a stop, the force required to bring a heavy truck traveling at the same speed to a stop

depends on the time involved

According to Newton's law of inertia, the result of walking much of the day is similar to tightening the head of a hammer when it's handle hits a solid surface so we are actually a little bit shorter in the

evening

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor...

exactly below the midpoint of the ceiling

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

increases

Whenever the net force on an object is zero, its motion change

is zero

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

its weight