Accelerated motion problem?

Question

The speedometer of a motor cycle registers values of 15 km/h, 21.8 km/h and 28.6km/h at intervals of 1.7 seconds. If this acceleration is maintained, after what further time will a speed of 62.6 km/h be attained.

Ok, i've found that the acceleration is 1.11m/s/s

Im not sure where to go from there? Any help is appreciated, thanks.

Answer 1

Use this formulae:

v^2=u^2+2as

v=final velo

u=initial velo

a=acceleration

s=time(that you need)

But change everyting to base unit (m/s not km/h)

Answer 2

Lets work in metres per second....

Acceleration = Change in Velocity / Change in Time.

Accel = (6.055556 - 4.16667) / 1.7 = 1.1111 ms^-2

Now we can use-:

v = u + at

62.6 = 28.6 + 1.111 * t

34 = 1.1111 * t

34 / 1.1111 = t = 30.60 seconds to reach the given final velocity.