Was work done on a book that fell from a desk to the floor? if so, what force was involved?

When a 5.0kg cart undergoes a 2.2m/s increase in speed, what is the impulse of the cart

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

The mantle is made up of which structural zones?