A rock is tied to a string and swung inner circle at a constant speed of 4 m/s. if the rock feels a centripetal acceleration of 5 m/s^2. what is the length of the string? A. 0.8 m
B. 1 m
C. 1.25 m
D. 3.2 m

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

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.