Question | Answer |
What example results in a helpful increase of friction? | sand applied to a slick sidewalk |
What example results in a helpful decrease of friction? | oil added to a car engine |
What is a force that opposes motion between two surfaces that are in contact? | friction |
Name two factors that determine the amount of friction. | the force and the roughness of the surface |
What is an example of an object opposed by kinetic friction? | a box sliding on a floor |
What is an example of an object opposed by static friction? | a worker pushing on a non-moving box |
Name an activity where friction is helpful. | car tires moving a car forward |
Name an activity where friction is harmful. | car engine parts wearing out |
What is a way NOT to reduce friction? | pouring sand on ice |
When a mover puts furniture on a dolly with wheels, which type of friction is the mover using to make his job easier? | rolling kinetic friction |
Why does friction occur? | the roughness of any object's surface |
What is a way to reduce friction? | wax skis before skiing down a slope |
What is friction? | a force that always acts to oppose motion |
When is friction greater? | when surfaces have more roughness |
What happens when force is applied to two surfaces in contact? | when force is applied, friction increases |
When a teacher tries pushing a large desk slowly across the classroom floor, but the large desk will not move, what is keeping the desk from moving? | static friction |
When two students help the teacher push a large desk slowly across the classroom floor, what resistance opposes the faster movement of the desk? | sliding kinetic friction |
When the teacher and students get a dolly to move a large desk, what force of resistance opposes the motion of the desk? | rolling kinetic friction |
Name three common items you might use to increase friction. | sand, work gloves, and sticky tape |