A 1200 kg car initally traveling at 20 m/s increases its speed to 28m/s. how much work did the cars engine have to do to cause this change

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.

Acar travels along a highway with a velocity of 24 m/s, west. the car exits the highway; and 4.0 s later, its instantaneous velocity is 16 m/s, 45° north of west. what is the magnitude of the average acceleration of the car during the four-second interval?

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?