If it takes him 10 seconds to stop what is the average stopping force over this time period?

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

Blank liquids and gases exert a buoyant force on objects placed in them

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?