Acyclist starts from rest and coasts down a 4.0∘ hill. the mass of the cyclist plus bicycle is 85 kg. ignore air resistance and friction.

a) after the cyclist has traveled 180 m , what was the net work done by gravity on the cyclist?

b) how fast is the cyclist going? in m/s

explain if

What happens to light waves from a star as the star moves away from earth?

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

8.29 two streams containing pyridine and acetic acid at 25°c are mixed and fed into a heat exchanger. due to the heat-of-mixing effect, it is desired to reduce the temperature after mixing to 25°c using a stream of chilled ethylene glycol as indicated in the diagram. calculate the mass flow rate of ethylene glycol needed. the heat capacity of ethylene glycol at these conditions is approximately 2.8 kj/(kg k), and the enthalpy change of mixing (δmixh) is given below.