Agirl on the swing throws a ball at the velocity of positive +7.5 m/s relative to the swing. when the ball leaves her hand, the girl has a velocity of +13.5 m/s relative to the ground. what is the velocity of the ball relative to the ground when she throws it?

a. +2 m/s
b.+6 m/s
c.+21 m/s
d. +101.25 m/s

Air enters a compressor operating at steady state at 1.05 bar, 300 k, with a volumetric flow rate of 93 m3/min and exits at 12 bar, 400 k. heat transfer occurs at a rate of 15.5 kw from the compressor to its surroundings. assuming the ideal gas model for air neglecting kinetic potential energy effects, determine the power in put in kw.

The number of passengers who arrive at the platform of a subway station for the 10 am train is a random variable with a mean of 120 and a variance of 16. find the lower bound of the probability that there will be between 100 and 140 passengers (round off to second decimal place).

What is a subatomic particle with a negative charge and very little mass?