Which accident will be more damaging, collision between two trucks moving with a speed 50 km/hr or collision between two cars moving with a speed of 50 km/hr? Explain.

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?

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Determine the age of a fossil if it had only one eighth of its original carbon-14 content remaining?