Two of the three tuning forks have known frequencies. when a 510 hz. fork and the unknown fork are struck together, four beats per second are heard. when a 505 hz. fork is struck with the unknown fork, beats are produced that are too numerous to count accurately. what is the frequency of the unknown fork?

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?