# Interesting sliding

A $60\si{\kilo\gram}$ man running at an initial speed of $\SI[per-mode=symbol]{4}{\meter\per\second}$ jumps on a $120\si{\kilo\gram}$ cart initially at rest. After reaching the top of the cart, the person slides on the cart's surface and finally comes to rest relative to the cart. The coefficient of friction between the cart and the person's feet is $0.4$, while the friction between the cart and ground can be neglected.

How long (in seconds) does the frictional force act on the person?

Details and Assumptions:

• Take $g=\SI[per-mode=symbol]{10}{\meter\per\second\squared}$.
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