A child stands in a valley and faces a large mountain. The child shouts “Hello!" and waits for the echo. The echo returns in 2.5 seconds. Assuming that sound
travels at 340 m/s in the valley, how far away is the mountain that caused the
echo?

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.

Aboy with a mass 25 kg climbs into a small tree. he sits on a branch that is 2.o m above to the ground. what is his gravitational potential energy above the ground?

Adiver named jacques observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the surface (where the pressure is 1.00 atm). the temperature at the bottom is 4.00 ∘c, and the temperature at the surface is 23.0 ∘c. what is the ratio of the volume of the bubble as it reaches the surface (vs) to its volume at the bottom (vb)? if jaques were to hold his breath the air in his lungs would be kept at a constant temperature. would it be safe for jacques to hold his breath while ascending from the bottom of the lake to the surface?