The decay of 40K has a half of 1.3 × 10 9 years. The age of the earth is estimated at 4.6 × 10 9 years. The decay of 40K is a major heat source for the earth's interior. Relative to today, how much more heat was produced by 40K in the early Archaeon era or 3.9 × 10 9 years ago?

The voltage applied across a given parallel-plate capacitor is doubled. how is the energy stored in the capacitor affected?

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.

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?