A solenoid that has length 30 cm, radius 1.2 cm, and 300 turns carries a current of 2.6 A. Find the magnitude of the magnetic field on the axis of the solenoid:

A12-g wad of sticky clay is hurled horizontally at a 100-g wooden block initially at rest on a horizontal surface. the clay sticks to the block. after impact, the block slides 7.5 m before coming to rest. if the coefficient of friction between the block and the surface is 0.65, what was the speed of the clay immediately before the impact?