A galloping pony speeds past you at 5 m/s. The frequency of the sound produced by the hooves on the dirt is 221 Hz. Assume the speed of sound to be 342 m/s. What is the observed frequency of the hooves after the pony has passed your position? 216 Hz 226 Hz 224 Hz 218 Hz

Aman pushes on a trunk with a force of 250 newtons. the trunk does not move. how much positive work is done on the trunk? 0.0 j -250 j 250 j 125 j

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.

The protons in a nucleus are approximately 2 ✕ 10^−15 m apart. consider the case where the protons are a distance d = 1.93 ✕ 10^−15 m apart. calculate the magnitude of the electric force (in n) between two protons at this distance.