George stands at the top of a 100 m tall cliff and tosses a ball straight up at 15.0 m/s. He planned to catch it, but missed and the ball fell to the ground below. If George tried to catch the ball at the same height he released it, how many seconds did he have to catch it

the temperature in kelvin of 2.0 dm3 of an ideal gas is doubled and its pressure is increased by a factor of four. what is the final volume of the gas

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.