Aplayground merry-go-round has radius 2.10m and moment of inertia 2500kg*m^2 about a vertical axle through its center, and it turns with negligible friction.

a)a child applies an 18.0 n force tangentially to the edge of the merry-go-round for 16.0s . if the merry-go-round is initially at rest, what is its angular speed after this 16.0s interval?

in rad/s
b)how much work did the child do on the merry-go-round?

c)what is the average power supplied by the child?

i understand the jist of the question but am stuck on where to start

What is the internal energy of 4.00 mol of diatomic nitrogen gas n2 at 455k

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!

What are chlorofluorocarbons and what impact do they have on the atmosphere?