A ball is dropped from rest from a high window of a tall building and falls for
4 seconds. Neglecting air resistance, the final velocity of the
ball is
m/s.
(g = -9.8 m/s2)

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Why don't you see your reflection in water with waves or repples

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in