I'm completely lost in physics, the kinematics and dynamics units.. my exam is coming up.. if a biker travelling at 6.4m/s sees biker b 34m ahead on the road travelling 4.7m/s. how far will biker b get before biker a catches him?

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

If a simple machine reduces the strength of a force, what must be increased?