Let's analyze each statement:
A) **The static friction in this case is more than the kinetic friction**: True. Static friction is the friction that keeps the crate from starting to move. Once the crate starts moving, the friction opposing its motion is called kinetic (or sliding) friction. Typically, static friction is higher than kinetic friction. That's why more force is usually required to initiate motion than to maintain it.
B) **It is easier to push the object on a smooth surface than on a rough surface to get it moving**: True. A smoother surface has less resistance or frictional force compared to a rough surface. As a result, it requires less force to get an object moving on a smooth surface than on a rough one.
C) **If we keep a heavy weight on the wooden crate we can get it moving easily as compared to when there is no block over it**: False. If you add a heavy weight on the crate, it increases the normal force. Since frictional force is directly proportional to the normal force (friction = μ x normal force), the frictional force will also increase, making it harder to move the crate.
D) **We need more force to get the crate to move initially compared to keep it moving**: True. As mentioned in option A, static friction (the friction when the crate is at rest) is generally greater than kinetic friction (the friction when the crate is moving). So, more force is required to overcome static friction and start the motion than is needed to overcome kinetic friction and maintain the motion.
Based on the above analysis, the true statements are: **A, B, and D**