What Is the Child's Acceleration Relative to the Ice?

[foreva_lynn]

On a cold winter morning, a child sits on a sled resting on smooth ice. When the 9.50kg sled is pulled with a horizontal force of 31.0 N, it begins to move with an acceleration of 2.50 m/s^2.
The 24.0kg child accelerates too, but with a smaller acceleration than that of the sled. Thus, the child moves forward relative to the ice, but slides backward relative to the sled. what is the acceleration of the child relative to the ice?

i dnt even know where to begin let alone attempt the problem. please help me out. and tell me the answer so that wen i calculate i will know what my answer will turn out like. thanks very much.

 

[Doc Al]

What must be the force between sled and child? Hint: Apply Newton's 2nd law to the sled.