$[4]$ Create and solve two Doppler Shist problems. One where the observer is moving, and one where the source$/$siren is moving.

Calculate the amount of heat needed to first melt $3$ Kg of ice, then to bring it srom $0C$ to $40C.$

$6.$ These waves interfere. Find the net$/$resultant wave at $t=2$ seconds. Refer to photo.

$7.$ What is the frequency of blue, green, red, infared, ultraviolet, and $x-$ray light? Which kind can we see? How do we use the others?

$8.$ Using the gravitational and centripetal force formulas, calculate:

$($a$)$ The force, in Neutons, of the earth on the moon. Convert to pounds.

$($b$)$ The speed of the moon.

$($C$)$ How much time it takes for the moon to orbit the earth.

C continued Use $C=2r$ moon. Convert to it takes for the pounds. to sind the distance the moon has to travel. cowvert to miles. Convert moon to orbit Earth. time to days, please!