Question

A car of mass 1000 kg develops a force of 500 N over a distance of 49 m. If initially, the car is at rest find

1. Final velocity
2. time for which it accelerates.

Answer 1

Mass of car = m = 1000 kg
Force = F = 500 N

Acceleration of car = a = `"F"/"m"=500/1000` = 0.5 ms⁻²

Initially velocity = u = 0
Distance covered = S = 49 m
Final velocity = v = ?
Time = t = ?

1. v² – m² = 2a S
v² – (0)² = 2 (0.5) (49)
v² = 49
v = 7 ms⁻¹

2. v = u + at
7 = 0 + 0.5t
0.5 t = 7
t = `7/0.5` = 14 s