Originally Posted by **sbnett** A 148-kg crate rests in the bed of a truck that slows from 61 km/h to a stop in 10 s.
I don't even know where to start. |

First find the (effective) push on the crate ....

This comes from the deceleration of the truck , you have the initial speed , and the end speed , and the time , from these three numbers you can get a deceleration in meters per second squared.