Hey, my teacher gave me these two problems for Homework and me nor anybody else in my class has no idea how to do them, any help would be greatly appreciated. 1. a 15.0kg block rests on a horizontal table and is attached to one end of a massless, horizontal spring. By pulling horizontally on the other end of the spring, someone causes the block to accelerate uniformly and readch a speed of 5m/s in .5s. In the process, the spring is stretched by .2m. The block is then pulled at a constant speed of 5m/s, during which time the spring is stretched by only .05m. Find (a) the spring constant of the spring and (b) the coefficient of kinetic friction between te block and the table. Now i used F applied=-kx with F applied=ma and x=displacement of the spring i got the spring constand to be equal to -750. That is the farthest i got, i dont know if its right or even how to begin part b. 2.A 30.0kg blcok is resting on a flat horizontal table. ON top of this block is resting a a 15.0kg block, to which a horizontal spring is attached, as the drawing illustrates. The spring constant of the spring is 325N/m. The coefficient of kinetic friction between the lower block and the table is .6, while the coefficient of static friction between the two blocks is .900. A horizontal force is increading in such a way as to keep the blocks moving at a constant speed. At the point where the upper block begins to slip on the lower block determine (a) the amount by which the spring is compressed and (b) the magnitude of the force F. I dont even know where to start any help would be greatly appreciated.