How come more coils on a slinky make the velocity higher ?

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

How does changing the frequency affect the energy of the wave?

You want to move a heavy box with mass 30.0 kg across a carpeted floor. you pull hard on one of the edges of the box at an angle 30∘ above the horizontal with a force of magnitude 240 n, causing the box to move horizontally. the force of friction between the moving box and the floor has magnitude 41.5 n . what is the box's acceleration just after it begins to move