Friction is mainly caused by rough surfaces

• True

• False

Without friction, walking across a room would be like walking on ice.

• True

• False

Life on Earth depends on gravity .

• True

• False

Gravity is the same on every planet and moon.

• True

• False

A tide is a rise of fall in water level near the ocean’s shore.

• True

• False

The motion of moving objects always is constant

• True

• False

The velocity of an object never changes.

• True

• False

____________ is the force that resists the movement of one surface past another.

• Air pressure

• Friction

• Clouds

____________ resists the motion of a skateboard´s wheels.

• static friction

• sliding friction

• rolling friction

Pushing a heavy box across the floor is hard because of ____________ .

• static friction

• sliding friction

• rolling friction