Calcular desde qué altura debe caer en punto muerto un automóvil de 7.000 n de peso para que adquiera la misma energía cinética que si marchase a 90 km/h

Lets say that an object of a certain volume has a certin mass. what happens to its mass when you double its volume?

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?

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects