Question

Force acting on the particle moving with constant speed is
(a) always zero
(b) need not be zero
(c) always non zero
(d) cannot be concluded


The answer is (b) need not be zero

Explain​

Answer 1

Answer:

Force acting on a particle moving with constant speed is 0. Theoretically.

Let's talk.

Okay, so there's this dude named David. So David needs to start from this given starting point and begin to drive his car.

Hence u = 0 because he starts from rest. And he accelerates and wins the race. Simple right? He accelerates and his v becomes something.

And that's what you need to find out the force exerted on the vehicle. You multiply the sum of David's mass and the car's mass and multiply it with the acceleration to find out the force.

However there's a catch. We could simply say,

"Oh, because of Newton's 1st law of motion, an object that would stay at rest will continue to stay at rest! So force is 0! So for any body that travels with uniform velocity, the force acting on it will be 0, because acceleration is 0!"

But there's another catch.

There's a little something called gravitational force. It doesn't do much but it does keep it intact to the Earth's surface. Gravitational force is also a force which can be equated. It is considered to be a force acting on all the bodies, whether they're in motion or they're not.

Hence it need not be zero. it can be zero in a one dimensional aspect and reasoning with Newton's Laws but if you think about gravity, you'll know that nothing in this planet would have 0 Newton's of force acting on it.