A car drives along a level road at a constant velocity...?

Question

The force needed to bring the car to equilibrium is 0. Why?
Please help me understand. Please don't post if you don't know or have no intention of helping.

Answer 1

Equilibrium means no change in motion thus no net force acting on the car. The sum of all forces on the car is equal to zero because it is moving at a constant speed by Newton's first law: An object stays in a constant state of motion unless acted on by a net external force.

Answer 2

All the forces at play have the vehicle in equilibrium - it is moving at a constant velocity.
Think of an airplane - There are weight force, lift force, forward force and drag. The weight equals the lift, the forward force equals drag. It is in equilibrium.
Just because the car is moving doesn't mean it isn't in equilibrium. If something started to slow it down, the equilibrium would no longer be zero, would it?

Answer 3

I am in physics right now and we are learning this kind of stuff now. It is 0 because the car is already going at a constant velocity so it is at its equilibrium.

Answer 4

Well, if it's going at a constant velocity it must already be at equilibrium, right? So no force is needed since no change has to be made.

Answer 5

the car's already in equilibrium b/c it's travelling at a constant velocity; it's speed isn't changing

Answer 6

If the velocity of the car is constant,that means acceleration of the car is zero.So the force is zero since force=mass*acceleration.

Answer 7

While I do not know how to answer this particular question, I do have a suggestion: go to the Mensa website. Our members are always willing to excitate brain cells for a good cause.