2016 · Q41
Which one of the following statements is not true?
general-sciencephysics-mechanics
- AThe gravitational force of earth acting on a body of mass 1 kg is 9.8 newton
- BThe force acting on an object of mass 5 kg moving with a uniform velocity of 10 m/s on a frictionless surface is zero
- CThe SI unit of weight is kg
- DThe momentum of a man having mass 100 kg walking with a uniform velocity of 2 m/s is 200 newton second
Explanation
Weight is a force, so its SI unit is the newton, not the kilogram (which is the unit of mass). The other statements are true: 1 kg weighs about 9.8 N, no net force acts on a uniformly moving body on a frictionless surface, and 100 kg x 2 m/s gives 200 N s of momentum. Hence (C) is not true.