Question

A vehicle as a mass of 1500 kg. What must be the force between the vehicle and the road if the vehicle is to be stopped with a negative acceleration of 1.7 $m{s^{ - 2}}$
A) 2550 N in a direction opposite to that of vehicle
B) 2550 N in a direction same to that of vehicle
C) 1550 N in a direction opposite to that of vehicle
D) 2550 N in a direction same to that of vehicle

Answer 1

The mass and acceleration of the object is given, so the force can be calculated using Newton’s second law of motion.
Newton’s second law of motion states that for a constant mass, the force is equal to the product of mass and acceleration of the body. Mathematically:
F = ma

Complete step by step answer: We have been given,
Mass of vehicle (m) = 1500 kg
Acceleration (a) = - 1.7 $m{s^{ - 2}}$
and we need to find Force (F).
From Newton’s second law, we have;
F = ma
Substituting the values, we have:
F = 1500 $\times$ (- 1.7)
F = -2500
The SI unit of force is Newton (N).
F = -2500 N
The negative sign shows that the direction of force is in the opposite direction to the motion of the object.
Therefore, the force between the vehicle and the road if the vehicle is to be stopped with a negative acceleration of 1.7 $m{s^{ - 2}}$ is 2500 N in a direction opposite to that of the vehicle and thus the correct option is A).

Note: This force that is present between the vehicle and the road is the force of friction which is an opposing force and makes the vehicle stop.
Force can be written in units $kgm/{s^2}$ but we prefer to write it in SI unit Newton.