the Depth of a sea is 6500 m and the speed of sound in water is . Calculate the time required for echo, when a sound wave is sent to bottom.) 1500 m/s ​

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.

By what primary heat transfer mechanism does the sun warm the earth?

An airplane is flying with a velocity of 240 m/s at an angle of 30.0∘ with the horizontal, as the drawing shows. when the altitude of the plane is 2.4km,a flare is released from the plane. the flare hits the target on the ground. what is the angle θ?