Motion

Question 1

Speed, velocity and acceleration

Answer 1

Speed: D/s = t (rearrange)
Velocity: Change in x/V = time (rearrange)
Acceleration: Change in V/acceleration = time (rearrange)

Question 2

Acceleration

Answer 2

Acceleration due to gravity = -9.8ms^-2
a = (Vf - Vi)/t = (V - u)/time
Positive when speeding up, negative when slowing down, units are ms^-2

Question 3

Kinetic Equations

Answer 3

V = u + at
V^2= u^2 + 2as
S = st + 0.5at^2

V=velocity
u=inital
t=time
a=acceleration
s=distance

Question 4

Newtons 3rd law

Answer 4

For every action there is an equal and opposite reaction.

The forces involved are opposite to each other and equal magnitude but the effect of each force can be quite different depending on the mass of the object.

Question 5

Momentum

Answer 5

This is a property of any moving object and is a vector.

P = mv
P=momentum(kgms^-1)
M=mass(kg)
V=velocity ms^-1

Change in momentum = F x change in time (kgms^-1)

Conservation of momentum - Pf = Pi
Pf = Pi
MaVi + MbVi = MaVf + MbVf

Change in momentum: Change in momentum = Force x change in time (kgms^-1)

Question 6

Inner-elastic collision

Answer 6

Scenarios where objects stick together after a collision.

MVa + MVb = Vf(Ma + Mb)

Question 7

Impulse Theorem

Answer 7

Change in P = Pf - Pi
Change in P = F x change in time

a = F/m
= v/t
F = mv/t

J = F x change in time (N.S)

Question 8

Energy

Answer 8

Ek = 0.5mv^2 - kinetic energy
Egp = mg change in height - Gravitational potential energy.
g= accelerating due to gravity (ms^-2)

When height is split multiply,
e.g: 3/4 of 13 m is 12 x 0.75 = 9m.