Question

A dog pushes a toy horizontally on a frictionless floor with a net force of 2.0\, \text N2.0N for 1.0\,\text m1.0m. How much kinetic energy does the toy gain?

Answer 1

Answer: 2 J

Explanation: Kinetic energy is possessed by a body due to virtue of its motion. A body gains kinetic energy when some work is done on it.

W = Δ K.E.

We know that work is said to be done on a body when a force causes displacement of the body.

W = F.s

It is given that net force on the toy, F = 2.0 N which displaces the toy by, s = 1.0 m.

Hence, work done on the toy, W = 2.0 N × 1.0 m = 2 J which is equal to the kinetic energy gained by the toy.  

Answer 2

Answer:

2.0 J

Explanation:

Since the surface is frictionless, we can solve the problem by using the work-energy theorem, which states that the work done on the toy is equal to the kinetic energy gained by the toy:

$W=\Delta E_k$

where

W is the work done on the toy

$\Delta E_k$ is the kinetic energy gained by the toy

The work done can be calculated as the product between the force applied on the toy and its displacement, so:

$W=Fd=(2.0 N)(1.0 m)=2.0 J$

Therefore, according to the work-energy theorem, the toy has gained 2.0 J of kinetic energy.