A slab of concrete is originally 18 m long. It is being tran…

A slab of concrete is originally 18 m long. It is being transported from a warmer region to a colder region. The temperature dropped from 24°C to -16°C. The coefficient of linear thermal expansion for this concrete is 12 x 10-6 (oC)-1. By what length will the slab of concrete contract (in cm)?

You are trying to hit a friend with a water balloon.  He is…

You are trying to hit a friend with a water balloon.  He is sitting in the window of his dorm room directly across the street.  You aim straight at him and shoot.  Just when you shoot,  he falls out of the window! Does the water balloon hit him? Assume that the shot does have enough speed to reach the dorm across the street