3.1.2 Linear Motion

a.) SUVAT equations

v = u + at

s = ½ (u + v)t

s = ut + ½at2

s = vt + ½at2

v2 - u2 = 2as

s = displacement

u = initial velocity

v = final velocity

a = acceleration

t = time

b.) When an object is falling through air, it experiences the force of weight which is it’s mass x the value of g 9.81.

c.)

Braking Distance

The distance travelled by the vehicle after the driver has applied the brake.

  • The braking distance increases at an even faster rate with speed

Stopping Distance

The distance it travels in the time it takes to stop in response to an emergency.

  • The stopping distance increases considerably with the speed of a car, this is because a car will travel further whilst braking before coming to rest.

Stopping distance = Thinking distance + Braking distance

Thinking Distance

The distance travelled by the vehicle from when the driver sees a problem and the brakes are applied.

  • The thinking distance is proportional to the initial speed, u, of the vehicle

  • The thinking distance increases proportionally with speed (i.e. if speed doubles, the thinking distance doubles)

Thinking Distance = Initial Speed x Reaction Time