1 The situation that will help reduce frictional force.
A. tearing of bike gears
B. applying lubricants to tires
C. rubbing together two hard objects
D. sliding big boxes on the ramp from the truck
2. When there is friction between moving parts of machine
A. Heat
B. Light
is produced
D. Speed
C. Oil
3. Friction is a force that acts in the
A. northern
B. opposite
direction of the intended motion of an object.
C. parallel
D. southern
4.
is a force of attraction that pulls together all matter
B. force
C. resistance D. gravity
A. energy
5. Which force always pulls objects downward?
A.. gravity
B air resistance C. friction force D support force
6. What force will be used by the brakes to stop a bike?
A friction
B gravity
C. magnetism
D. pitch
7.Which type of friction is the weakest?
A.Fluid
B.air resistance
C.Sliding
D.Static
8.Which of the following has the greatest friction?
A.polished floor
B.sandy floor
C.tiled floor
D.wet floor
9.Which shows that friction is undesirable?
A.pushing furniture
B.lighting a matchstick
C.walking on wet floor
D.using breakes when approaching a stoplight
10.The boat sailing on the sea slows down.What kind of friction is acting on it?
A.fluid friction
B.rolling friction
C.sliding friction
D.static friction