Question

Question 8 An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s −2 ?

Class 9 - Science - Force and Laws of Motion Page 128

Answer 1

Given,

Mass of the vehicle, m = 1500 kg

Acceleration, a = – 1.7 m s–2

Force acting between the vehicle and road, F =?

We know that, F = m x a

Therefore, F = 1500 kg X 1.7 m s–2

Or, F = – 2550 N

Thus, force between vehicle and road = - 2550 N. Negative sign shows that force is acting in the opposite direction of the vehicle.
Given,

Answer 2

Here, m = 1500 kg,

a = - 1.7 m s-²​

Therefore, F = ma

= - 1500 × 1.7

= -2550 N

Negative Sign shown that the direction of the force is opposite to the direction of motion of the vehicle.