Mechanics

Question 1

Moments

Answer 1

Moment = force x perpendicular distance along the line of action about the pivot

Question 2

Velocity

Answer 2

Velocity = change in distance/ change in time

Question 3

Acceleration

Answer 3

Acceleration = change in velocity/ change in time

Question 4

SUVAT

Answer 4

S = Displacement
U = Initial velocity
V = Final velocity
A = Acceleration
T = Time

Question 5

Newtons first law

Answer 5

The velocity of an object will not change unless a resultant force acts on it

Question 6

Newtons second law

Answer 6

The acceleration of an object is proportional to the resultant force acting on it.
F = ma

Question 7

Newtons third law

Answer 7

If an object “A” exerts a force on object “B”, then object B exerts an equal but opposite force on object B

Question 8

suvat (v)

Answer 8

v = u +at

Question 9

suvat (s₁)

Answer 9

s = ut + ½at²

Question 10

suvat (v²)

Answer 10

v² = u² + 2as

Question 11

suvat (s₂)

Answer 11

(v + u)t / 2

Question 12

Time (up)

Answer 12

2Uᵧ/a

Question 13

Time (suicide)

Answer 13

√2Sᵧ

/a

Question 14

Range (up)

Answer 14

Uₓt

Question 15

Range (suicide)

Answer 15

Uₓt

Question 16

Max height (up)

Answer 16

Uᵧ²

/2a

Question 17

Final speed (suicide)

Answer 17

√Uₓ²+(at)²

Question 18

Principle of Moments

Answer 18

For a body to be in equilibrium the sum of the clockwise moments about any point equals the sum of the anticlockwise moments about the same point

Question 19

What is a couple

Answer 19

A pair of forces of equal size which act parallel to each other but in opposite directions. Causes a turning effect (a moment)

Question 20

What is freefall

Answer 20

Where there is gravity acting on object and nothing else

Question 21

Why do all objects fall at the same speed in a vacuum

Answer 21

f = ma
the only force acting is weight so W = mg
ma = mg (m cancels out)
a = g

Question 22

Equations of motion in freefall

Answer 22

v = gt
v² = 2gs
s = 1/2gt²
s = vt/2

Question 23

What is terminal velocity

Answer 23

Terminal velocity happens when frictional forces equal the driving force

Question 24

Momentum

Answer 24

m x v
linear momentum is always conserved
momentum before = momentum after

Question 25

elastic vs inelastic collisions

Answer 25

Elastic: Momentum is conserved, KE is conserved
Inelastic: Momentum is conserved, KE is not conserved

Question 26

Impulse

Answer 26

The product is force and time

The area under a force time graph

Question 27

Work done

Answer 27

Force x distance

Force x distance x cos0

Question 28

Power

Answer 28

P = force x velocity