Question

According to the work-energy theorem, if work is done on an object, its potential and/or kinetic energy changes. Consider a car that accelerates from rest on a flat road. What force did the work that increased the car’s kinetic energy?
1. the force of the car engine

2. air resistance

3. the friction between the road and the tires

4. gravity

Answer 1

Answer:

The force of the car engine.

Explanation:

The work- energy theorem states that the work done on an object is equal to the change in its kinetic energy. Its expression is given by :

$W=\dfrac{1}{2}m(v^2-u^2)$

Also, W = F.d

$Fd=\dfrac{1}{2}m(v^2-u^2)$

Where

F is the force applied by the engine of car

d is the displacement

m is the mass of an object

u is the initial speed

v is the final speed

So, the force of the car engine increased the car’s kinetic energy. Hence, this is the required solution.