What is the force of tension in a rope that spins a 250 g object in a vertical circle with a radius of 50 m if the mass at the top of the loop is traveling at 3 m/s ?

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?