The center C disk, radius R and weight P is located in balance on the rough horizontal surface fixed to the ground. What are the greatest horizontal forces of magnitudes F and Q applied in A and C that can act simultaneously on the disc, without it moving? The coefficient of friction between the disc and the surface is 0.5 and the vertical distance between the points of application of both forces is r.

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!

Why do astronauts in the space shuttle weigh less?

First to answer will be the brainliest i need the answer asap