Force and Motion Review

Force and Motion Review

Multiple Choice

Forces can cause objects to

• stop moving only.

• start moving only.

• start moving, change direction, or stop moving.

• change direction only.

Forces

• Forces can stop - pushing, pulling, friction, gravity

• Change Directions- think about hitting a baseball.

• Change from potential to Kinetic (moving)

Multiple Choice

According to Newton's third law of motion, when a hammer strikes and exerts force on a nail, the nail

• disappears into the wood.

• exerts an equal force back on the hammer.

• creates a friction with the hammer.

Newton's Laws

• 1st Law- Objects in motion will stay in motion; objects at rest will stay rest.

• 2nd Law- More mass needs more force/ more force = more acceleration.

• 3rd Law - For every action, there is an equal and opposite reaction.

Multiple Choice

Jasmyn can run 50 yards in 10 seconds and Jaylah can run 100 yards in 20 seconds. Who has a faster speed? (Remember speed equals distance divided by time.)

• They both have the same speed.

• Jasmyn

• Jaylah

50/10 = 5 = 100/20

Both have a quotient of 5.

Multiple Choice

The tendency of an object to stay in motion or at rest until a force acts upon it is

• frame of reference

• movement

• inertia

• relation

Multiple Choice

The direction of the frictional force on a moving object is...

• never responsible for stopping the motion of the object.

• opposite to the motion of the moving object.

• the same as the motion of the moving object.

• not going to alter the acceleration of the moving object.

Friction

One surface or object rubbing against another.

High Friction surface examples: Sandpaper, Grass, Carpet, rough surface

Low Friction- Hardwood floors, ice, smooth surfaces

Multiple Choice

Distance divided by time describes

• speed

• Acceleration

• velocity

• momentum

Distance Time Graphs

Multiple Choice

Which of the following is an example of increasing friction intentionally?

• adding grease to gears on a bike

• throwing sand on an icy driveway

• waxing skis

Friction Reduced or Increase

• Increase friction because the surface is unsafe or get a better grip - cleats or sand

• Decrease friction to go faster- like waxing skis or greasing gears

Multiple Choice

An object that has kinetic energy must be...

• lifted above earth's surface.

• at rest

• in motion.

• none of the above

Potential vs. Kinetic

Potential- The higher- the more potential

Kinetic is moving.