An object of mass 6 kg is sliding on a frictionless horizontal surface with a uniform speed of 8 m/s. The force required to keep the object moving at the same speed along the same straight line is

A : 27 newtons
B : 54 newtons
C : 0 newtons
D : 18 newtons
General Science
Physics
Motion
Answer
Option 3 : 0 newtons
Explanation

The correct answer is 0 newtons.

CONCEPT:

  • Newton's first law of motion: A body doesn't change its states until an external force acts on it.
  • The force is the product of mass and Acceleration

Force = Mass × Acceleration

CALCULATION:

  • The body is moving with a constant velocity of 8 m/s, So acceleration in the body is zero.

                             Force = Mass × Acceleration

                             Force = 6 Kg × 0

                             Force = 0 N

Mistake Point:

  • Do not apply friction law as the given surface is frictionless.
  • Friction law is not applicable in this case.