If you perform 40 j of work lifting a 10-n box from the floor to a shelf, how high is the shelf?

How are calculation for velocity and speed different

Part a constants huck finn walks at a speed of 0.60 m/s across his raft (that is, he walks perpendicular to the raft's motion what is huck's velocity (speed and direction) relative to the river bank? express your answer to three significant figures and include the appropriate units. relative to the shore)

Idon’t quite understand this problem