Why is a 5 rupees coin attracted by a magnet? name the metal present in the coin

An athlete is holding 24 lb of weights at a height of 6 inches above the stack as shown. to lower the weights, she applies a constant force of 5 lb to the handle. determine the velocity of the weights immediately before they hit the stack.

At what time will the interfering waves have an amplitudeof zero?

Matter that emits no light at any wavelength is called