Adog wishes to swim across a slow-moving stream. the dog can swim at 2.0m/s in calm water. the velocity of the current is 3.0m/s. the distance directly across the stream is 50m.
a) how long does it take dog described above to swim 50m in a bost of water that has no current?
b) how far downstream will current have carried the dog in the time it takes the dog to get across the stream?
c) calculate dog’s resultant velocity relative to bank from where the dog started.

The step-down transformer gives a current of 10a at 24v if the primary voltage is 240v calculate the 1_primary current 2_the power input 3_the power output

There is a theory that indicates that dinosaurs became extinct when about 65 million years ago, a large asteroid hit the earth surface. dust caused by this collision blocked the sunlight reaching the earth's surface and many forms of life became extinct due to the cold. fearing this threat, how large the radius of an asteroid should you be looking for if the dangerous asteroid size is approximately the same as the one that killed the dinosaurs? available data suggests that about 18% of that asteroid's mass ended up as a dust spread evenly over earth after eventually settling out of the upper atmosphere. about 0.0180 g/cm^2 of dust, which is chemically different than the earth's rock, covered the earth's surface. typical asteroids have a density of about 1.9 g/cm^3. now that we know the size of the asteroid, how much energy was released during impact, assuming all of it was just the kinetic energy of the asteroid right before the impact?

In a system, when potential energy decreases, then entropy also decreases. true false