A rock climber carry a backpack has a total weight of 600 N. How much work is done when she climbs 12 m in 10 sec?
a 50 j
b. 60 j
C 720 j
d. 7200 j

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 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

Explain why electric current cannot exist if a current doesn't have a voltage source.

Is the portion of the electromagnetic spectrum that has a frequency just above that of visible light.