Question

As a box is pushed 30 meters across a horizontal floor by a constant horizontal force of 25 newtons, the ki- netic energy of the box increases by 300 joules. How much total internal energy is produced during this process?

1. 150j
2.250j
3. 450j
4. 750j

Answer 1

The internal energy produced during this process is 450 J.

Answer: Option C

Step-by-step explanation:

We know, that work done to perform a displacement will be equal to the change in the kinetic energy as per work energy theorem. Also the work done on that object can be determined by the product of force with displacement.

As the force here is applied in horizontal direction with magnitude of 25N. And with this force, the box got displaced by 30 m. So,

`\text { Workdone }=\text { Force } * \text { Displacement }=25 * 30=750 \mathrm{J}`

But, according to work energy theorem, the workdone should be equaled to the variation in kinetic energy. While here, the kinetic energy has been found to change as 300 J in positive side.

So, the variation in kinetic energy is not matching with the work done to displace the box. Hence, it can be concluded that the difference in work done and modified kinetic energy will be giving the total internal energy of the box. Thus,

`Total internal energy of the box = Work done - Kinetic energy =750-300=450 \mathrm{J}`