A large crate of mass m is placed on the back of a truck but not tied down. As the truck accelerates forward with an acceleration a, the crate remains at rest relative to the truck. What force causes the crate to accelerate forward?
A、thenormalforce;
B、theforceofgravity;
C、theforceoffrictionbetweenthecrateandthefloorofthetruck;
D、the“ma”force;
E、noneofthese.
发布时间：2025-07-15 19:40:11
