Three children use the same skateboard. i) 20-30kg, ii) 30-40 kg iii) 40-50kg Which child can move the skateboard using the smallest pushing force? Justify your choice.

i) 20-30 kg

Explanation:

The child with the smallest mass range of 20-30 kg will require the smallest force to move his skate board because he/she has a smaller inertia force to overcome. The mass of a body is the measure of the inertia forces of the body. The inertia force makes it difficult for a body at rest to start moving, and a body already in motion to stop moving.

When the children try to move the skateboard, they exert a force that is proportional to the product of their mass and the acceleration with which they start moving. This force must exceed their body's inertia force before they would start moving.

from

F = ma

where F is the force required

m is the mass

a is the acceleration

We can see that for the given mass ranges, the children with the larger mass range will require more force in order to move their skateboard. Consequently, the child with the smallest mass range will require the smallest pushing force to move his skate board.