Understanding the Concepts

* Work: Work is done when a force causes an object to move a certain distance. It's calculated as: Work (W) = Force (F) x Distance (d)

* Force of Gravity: The force of gravity pulls objects towards the Earth. This force is calculated as: Force (F) = Mass (m) x Acceleration due to gravity (g)

* Acceleration due to gravity (g): This is approximately 9.8 m/s².

Calculations

1. Calculate the force of gravity on the child:

F = m * g

F = 15 kg * 9.8 m/s²

F = 147 N (Newtons)

2. Calculate the work done:

W = F * d

W = 147 N * 1.2 m

W = 176.4 J (Joules)

Answer: The mother does 176.4 Joules of work lifting the child.