Mechanics

Question 1

Moment of a force

Answer 1

Force x perpendicular distance from the line of action of the force to the pivot

Question 2

Moment of a couple

Answer 2

One force x distance between both forces

Question 3

Centre of mass

Answer 3

The point in a body where the whole weight appears to act

Question 4

SUVAT equations

Answer 4

v=u+at
s=(a+b)/2 x t
s=ut+1/2at^2
v^2=u^2+2as

Question 5

projectile motion rules:

Answer 5

-No horizontal force/acceleration
-Vertical component of a is constant if air resistance is ignored
-initial velocity=0
Highest point-> vertical v=0

Question 6

(Universal rule) for mechanics 4

Answer 6

Component x (tension, thrust, drag, weight etc) - parallel component of y (opposing forces) = Fr (ma)

Question 7

Newtons 1st law (Law of inertia)

Answer 7

An object will remain at rest or cat constant velocity unless acted on by an unbalanced force

Question 8

Newtons 2nd law

Answer 8

The rate of change of momentum of an object is proportional to the resultant force on the object in the same direction

Question 9

Newtons 3rd law

Answer 9

When body A exerts a force on body B, body B exerts a force equal in magnitude but opposite in direction on body A

Question 10

(Newton’s second law) Fr

Answer 10

=m x (Δv/Δt)
=v x (Δm/Δt)
[p=mv]
=Δp/Δt

Question 11

Impulse definition

Answer 11

The impulse of a force is the product of the force and the time for which the force acts

(Area under a force/time graph)

Question 12

Impulse =

Answer 12

F x Δt
-> (F x Δt)= Δp

Question 13

Conservation of momentum principle

Answer 13

Total momentum before collision = total momentum after collision