Force and Friction

Four different students take turns pushing a large, heavy ball on the school parking lot. What is the best way to determine which student used the most force to push the ball?

• compare the sizes of the students
• compare the ages of the students
• compare the distances that the ball rolled
• compare the number of times the ball was rolled

Pam ran down the sidewalk to school with her empty backpack. After school Pam’s backpack was loaded with books. Which best describes the force required to carry her book bag home?

• It took the same amount of force to carry the loaded book bag home.
• It took a greater amount of force to carry the loaded book bag home.
• It took a lesser amount of force to carry the loaded book bag home.

How does friction affect speed?

• more friction decreases speed
• more friction increases speed
• less friction decreases speed

Matt had a toy truck weighing 15 grams and a toy car weighing 6 grams. Using the same amount of force on each toy, he pushed them both across his desk. The car reached the other side of the desk in 1.5 seconds, but it took the truck 3.5 seconds to reach the the other side of the desk. Why did the car travel the same distance in a shorter amount of time?

• The car had less mass and traveled at a faster speed than the truck.
• The car had more mass and traveled at a faster speed than the truck.
• The truck had more mass and traveled at a faster speed than the car.

Which of the following would increase the motion of a ball after it is kicked?

• a high, grassy surface
• a surface sloped uphill
• a surface sloped downhill

Two toy race cars are going to be raced down the same ramp. Which information is most helpful in predicting which car will win the race?

• length of the ramp
• volume of the cars
• slope of the ramp
• mass of the cars

Why are new tires on a car better than older, worn tires?

• New tires have less mass than older tires.
• New tires are less affected by gravity than older tires.
• New tires allow the car to travel faster than older tires.
• New tires provide more friction on the road than older tires.

Which best describes the force of gravity?

• a pulling force
• a pushing force
• a change in mass
• a change in speed

James and Alex are kicking a ball back and forth. Alex kicks the ball in James’s direction, but the ball stops just before it reaches James. Which most likely caused the ball to stop?

• friction
• gravity
• change in mass of the ball
• change in shape of the ball

A person is pushing a lawnmower. Which best describes what is occurring?

• Mass is being applied to the lawnmower.
• Force is being applied to the lawnmower.
• There is no friction acting on the lawnmower.
• There is no gravity acting on the lawnmower.