Mechanics

Question 1

Moment

Answer 1

The turning effect of a force perpendicular to an object.
Moment = fd

Question 2

Couple

Answer 2

Two moments of equal size acting in opposite direction

Question 3

Principle of mometns

Answer 3

For a body to be in equilibrium, Σ clockwise moments about any point = Σ anticlockwise moments about the same point

Question 4

Centre of mass

Answer 4

The single point where the whole weight of an object acts through

Question 5

Displacement

Answer 5

The distance an object has travelled from its starting position in a general direction

Question 6

Velocity

Answer 6

Rate of change of displacement

Question 7

Law of conservation of moment

Answer 7

In a closed system, the momentum of a system remains constant

Question 8

Newton 1

Answer 8

Every body continues in its state of rest or at uniform motion in a straight line unless acted upon by an outside force

Question 9

Newton 2

Answer 9

Size of resultant force acting on an object ∝ object’s rate of change of momentum

Question 10

Newton 3

Answer 10

For every action, there is an equal an opposite reaction

Question 11

v = u + at (1)

Answer 11

a = (v - u) / t –> m of line

Question 12

s = ut + 1/2at^2

Answer 12

s = ut + (1/2)t(v - u)
sub in at = v - u from (1)
s = ut + 1/2(at^2)

Question 13

s = ((u + v)/2)t (3)

Answer 13

s = ((u + v)/2)t –> s is area under curve = trapezium

Question 14

v^2 = u^2 + 2as

Answer 14

v = u + at (1)
t = (v - u)/a (rearranged 1)
s = ((u + v)t )/ 2 (rearranged 3)
s = ((u + v)(u - v))/2a (sub rearranged 1 into t)
Expand and rearrange into (4)