How many butter, which has a usable energy content of 6.0 cal/g (= 6000 cal/g), would be equivalent to the change in gravitational potential energy of a 64 kg man who climbs 7.07 km? assume that the average g for the climb is 9.80 m/s^2.

Aparticle initially moving east with a speed of 20.0 m/s, experiences an acceleration of 3.95 m/s, north for a time of 8.00 s. what was the speed of the particle after this acceleration, in units of m/s? give the answer as a positive number.

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

Acid precipitation chemically weathering a 5.0-kg limestone rock . which coukd be the result ?