Question

What is the acceleration of a vehicle that changes its velocity from 100 km/h to a dead stop in 30 s ? Answer in units of m/s 2 .

Answer 1

Answer:

a = $-\frac{25}{27}$ m/s²

Explanation:

Acceleration (a) = (final velocity - initial velocity) ÷ (final time - initial time) =  $\frac{v_{f} - v_{i} }{t_{f} - t_{i} }$

Converting the speed from km/h to m/s;

100 km = 100000m

1hr = 3600s

∴ 100km/hr ⇄ $\frac{100000 m}{3600 s}$ = $\frac{250}{9} m/s$

Acceleration = $\frac{0 - 250/9}{30}$ = $-\frac{250}{9 * 30} = -\frac{25}{27}$ m/s²

i.e deceleration = $\frac{25}{27}$ m/s²