A hockey puck (mass = 2.5 kg) leaves the players stick with a speed of 40 m/s and slides on the ice for 40 meters before coming to rest. What is the friction coefficient between the puck and the ice?
(unitless)

Which type of electromagnetic waves are dangerous enough to be used to kill cancerous cells? (a)gamma rays (b)visible light (c)infrared light (d)microwaves

The intensity of a polarized electromagnetic wave is 12 w/m^2. part a) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=0∘ with the plane of polarization? part b) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=30∘ with the plane of polarization? part c) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=45∘ with the plane of polarization? part d) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=60∘ with the plane of polarization? part e) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=90∘ with the plane of polarization?

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?