The rotating light on a lighthouse is 400 feet from a cliff. it completes one rotation every 10 seconds. the equation representing the distance, d, in feet that the center of the circle of light is from the lighthouse is d(t) = 400sec (πt/5). what is the period of d(t)? (enter only the number.)

Why is there friction between objects

Assuming weightless pulleys and 100% efficiency, what is the minimum input force required to lift a 120 n weight using a single fixed pulley?

The key to stability is feedback between the reservoir and the fluxes into and/or out of the reservoir. assume that the rate of outflow from a reservoir depends on the size of the reservoir according to the following relationship: outflow rate= k x (size of reservoir), where k is a constant. a reservoir of water has a volume of 5000 liters, and the rate of outflow at steady state is 25 liters per minute. what is k? (give both the numerical value and its units.) what is the residence time? what is the relationship between k and the residence time?