Which type of wave has a frequency just higher than violet visible light and is used by the skin to produce vitamin d?

a. x-rays

b. microwaves

c. light

d. ultraviolet

All the simple machines make work easier to do by changing the or of a force. a. size; type b. work; type c. size; direction d. type; direction

Which diagram correctly demonstrates the various forces acting on a ball moving horizontally with some speed?

An ideal otto cycle has a compression ratio of 10.5, takes in air at 90 kpa and 40°c, and is repeated 2500 times per minute. using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kw of power.