Two sound sources emitting plane waves separated by 12 meter vibrates according to law y1=3cos4πt and y2=4sin4πt respectively. A point in the medium is at a position 8m from first source and 4m from second on the line joining two sources. The sources out waves of velocity 32 m/s. find equation of the motion of the particles (y1, y2are in centimeter and t is in second)  
A)  yR=5sin(4πt+tan−1(43))
B)  yR=−5sin(4πt+tan−1(34))
C)  yR=−5sin(4πt+tan−1(43))
D)  yR=5sin(4πt+tan−1(34​

Will give brainliest! jay rides his 2.0-kg skateboard. he is moving at speed 5.8 m/s when he pushes off the board and continues to move forward in the air at 5.4 m/s. the board now goes forward at 13 m/s.a. determine jay’s mass.b. determine the change in the internal energy of the system during this process.(express your answer to two significant figures and include the appropriate units.)

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.