Summarize It

Which of the following shows equal forces?

• person riding a bicycle up a mountain

• person on a bicycle who is stopped at a stop sign

• person riding a bicycle down a mountain

• person riding a bicycle in circles

Which of the following does NOT belong?

• Speeding up

• Slowing down

• Sitting motionless

• Changing directions

For an object to remain at rest, which of the following must be true?

• The forces acting on it are equal.

• There is no friction.

• Gravity does not act on it.

• The object has no mass.

Forces that act on objects cause a transfer of ________.

• energy

• mass

• momentum

• temperature

5. Equal forces create no ________ in motion.

Which of the following describes a balanced force? Choose TWO answers.

• A dog running

• A roller coaster going downhill

• A box sitting on the ground

• A ball bouncing

• A bike leaning against a wall

Which of the following describes an unbalanced force?

• A car rolling down a hill

• A ball resting on the ground

• A dog sleeping

• A parked car

Is it BALANCED? 

• Yes
• No

Students conduct experiments to investigate friction. Which experiment will best test the effect of friction on objects?

• Drop two balls from the same height at the same time

• Roll two marbles on the carpet from the same starting point at the same time and with the same amount of force

• Roll three marbles across three different surfaces from the same starting point at the same time and with the same amount of force

• Release two balls from the top of a ramp at the same time

For a class demonstration a student turned off the lights in the classroom. The student then shined light from a flashlight through a hole in a piece of cardboard. The class saw the narrow beam of light continue until another student placed a mirror in the light’s path. The light did not continue past the mirror because —

• A light cannot travel very far

• the mirror absorbed all the light

• the light was refracted back to the light source

• light travels in a straight line and cannot go around objects