Friction and impact

Question 1

what is the equation for friction?

Answer 1

F = μ ×R

Frictional force = coefficient of friction ×normal reaction force

Question 2

what does friction depend on?

Answer 2

Friction is dependent on mass

▫Increased mass = increased reaction force
Therefore a greater frictional force because μ does not change

Question 3

what is impact?

Answer 3

Two (or more) bodies exert relatively large forces on one another over a very small time period

Question 4

what is the coefficient of restitution (e)?

Answer 4

The coefficient of restitution (e)describes the relative elasticity of an impact

▫It is typically measured on a scale of 0 to 1

Question 5

what is the coefficient of restitution equation?

Answer 5

-e = (v1–v2) / (u1–u2)

v = final velocity 
u = initial velocity
1 = object 1
2 = object 2

▫e = √ (height bounce/ height drop)