Schoolnet Review - Gravity and Friction

Two identical balls are pushed with the same force. One ball is pushed along a flat surface and the other ball is pushed down a slanted surface. Which ball will travel faster and why?

• the ball on the slanted surface, because of decreased friction

• the ball on the slanted surface, because of increased gravity

• the ball on the flat surface, because of decreased gravity

• the ball on the flat surface, because of increased friction

How would the absence of friction affect a marble traveling on a long, straight path?

• The marble’s speed would decrease.

• The marble’s speed would increase.

• The marble would stop immediately.

• The marble would remain at constant speed.

When Anna tells her father that her bicycle is hard to pedal, he oils the chain. How does this make her bike easier to ride?

• Friction on the bike has increased.

• Friction on the bike has decreased.

• Gravity on the bike has increased.

• Gravity on the bike has decreased.

Which is the best example of a pushing force that reduces the speed of an object?

• a bat hitting a baseball

• a brake rubbing against a wheel

• a pedal turning the wheels of a bicycle

• a skateboard wheel rolling against pavement

Which is the best way to reduce the amount of friction on a plane?

• use different fuel in the plane

• change the shape of the plane

• increase the speed of the plane

• increase the weight of the plane

John stands at the top of a steep hill and pushes a ball over the edge with his foot. Which force causes the ball to continue rolling down the hill?

• mass

• gravity

• friction

• air resistance