1) A person standing on edge of cliff throws 3 identical rocks with same speed. Rock X is thrown vertically upward, rockY is thrown horizontally and rock Z is thrown vertically downward. Assuming elevation loss of 3 rocks is same (base of cliff is flat) which rock hits the ground with the same speed? Explain.
2) You carry 7.0 kg bag of groceries 1.2m above ground at constant velocity across a 2.3 m room. How much work do you do on bag in process?