A child with a mass of 30 kg slides down a slide at an angle of 40º from the horizontal. She accelerates at 1.3 m/s2. Calculate the magnitude of the frictional force on the child. The final answer is 150N, but how do I show the work to get this answer?

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.