I drop a penny from the top of the tower at the front of fort collins high school and it takes 1.85 seconds to hit the ground. Calculate the velocity in m/s at the time of impact

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?

In the first law of thermodynamics, triangle e=q-w, what does q stand for

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?