Answer:
See explanation
Step-by-step explanation:
The question is incomplete, as the required parameters are missing. The general solution to this is as follows;
First, get the mass (m) and the acceleration (a) of the sled
So, the force (f) to stop the sled is:
---- Newton 2nd law
However, the force to stop the sled will be in the opposite direction of the sled.
So:

Assume that:


The required force is:


