If you push a chair across the floor at a cibstant velocity how does the force of friction compare with the force you exert?

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 11.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.80 m/s; (b) he is then lifted at the constant speed of 4.80 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 78.0 kg rescue by the force lifting him during each stage

What are similarities and differences between refraction, reflection, diffraction and absorption?

Rohit is trying to tune an instrument