Physics- Forces and Braking

Question 1

Friction is a force that opposes the motion of an object. It always acts in the opposite direction to the motion of an object. Friction is measured in…

Answer 1

Newtons

Question 2

Friction causes some or all of the energy transferred from the moving object to be transferred into thermal (internal) energy- the surfaces in contact get…

Answer 2

warmer

Question 3

Two examples of friction being useful:

Answer 3

object to start or stop moving

screws and nails to hold

Question 4

Friction can also be a nuisance. Friction is always present on Earth but its effects can be reduced by:

Answer 4

a lubricant: oil, smooth polished surfaces
use rollers, ball bearings
use a streamlined, more aerodynamic shape
cushion of air

Question 5

The friction produced will definitely depend on:

Answer 5

the mass of the object
the materials/smoothness of the contact surfaces
the speed of movement

Question 6

overall stopping distance =

Answer 6

thinking distance + braking distance

Question 7

thinking distance =

Answer 7

speed x reaction time