Momentum before the hit:
p = mv = 0.01 * 300 + 1 * 0
Momentum after the hit:
p = 0.01 * 150 + 1 * v
Momentum is conserved:
0.01 * 300 = 0.01 * 150 + v
3 = 1.5 + v
v = 1.5
The velocity of the block after the collision is 1.5 m/s.
At stp (standard temperature and pressure), the temperature is T=0 C=273 K and the pressure is p=1.00 atm. So we can use the ideal gas law to find the number of moles of helium:

where p is the pressure (1.00 atm), V the volume (20.0 L), n the number of moles, T the temperature (273 K) and

the gas constant. Using the numbers and re-arranging the formula, we can calculate n:
The answer to the statement is true because the day is of the logical proportion it has to be time.
The answer would be B: The ground exerts an equal force on the golf ball.