Motion, Force, and Pressure

It's a basic law of physics that for every force, or action, there is ...

• A decrease force, or action.
• An equal force in the same direction.
• An increased force, or reaction.
• An equal and opposite force, or reaction.

Which does not describes acceleration?

• A bird flying south at 30 mph slows to land in a tree.
• A snake slithers around the base of a tree.
• Mrs. Knickmeyer walks faster down the hallway because she sees chocolate cupcakes.
• Mrs. Hoppe walks at the same speed down a straight hallway because she already has a chocolate cupcake.

Which term describes the tendency of a moving object to continue moving at the same velocity unless an unbalanced force acts on it?

• Friction
• Inertia
• Gravity
• Accleration

Which unit would be acceleration?

• N
• m/s
• Pa
• m/s/s

What is the definition of acceleration?

• A change in velocity.
• The direction of motion.
• An object's speed multiplied by its mass.
• The rate at which an object's position changes.

According to the law of conservation of momentum, when two objects collide in the absence of outside forces...

• velocity decreases
• velocity increases
• the objects have the same momentum before and after they collide.
• the objects have more momentum after they collide than they did before.

Which of the following would exert the greatest gravitational force on a body?

• a bar magnet.
• a molecule.
• a planet.
• a person.

A skydiver jumps out of a plane.  She falls downward at a very fast speed.  When she opens her parachute, she slows down.  What friction slows her fall?

• friction
• gravity
• air resistance
• rolling friction

A satellite orbits Earth.  What would happen if Earth's gravity suddenly disappeared?

• The satellite would continue to orbit Earth.
• The satellite would move into space in a straight line.
• The satellite would stop moving.
• The satellite would fall to Earth.

Objects fall at different rates on planet Earth because of their...

• different weights.
• surface area to weight ratio.
• mass.
• density.