16. Suppose a person that has a mass of 60kg is standing on the ground. The force of friction between the person and the ground is a constant 300N. The person pushes horizontally against a truck with a force of 400N (the truck has mass 5000kg). The force of friction between the ground and the truck is also a constant 300N. a. What is the magnitude of the force that the truck exerts on the person?
b. Draw two free body diagrams. In one show the horizontal forces acting on the truck and in the other show the horizontal forces acting on the person. (use Newton’s third law to determine the force that the truck exerts on the person)
c. Determine the acceleration of the person using Newton’s second law and the forces acting on the person.
d. Determine the acceleration of the truck using Newton’s second law and the forces acting on it.
e. With these values for acceleration, how fast will the person and the truck be moving after half a second if both start from rest?

The inside surface of a cylindrical-shaped cave of inner diameter 1.0 m is continuously covered with a very thin layer of water. the cave is very long and it is open on both ends. the water on the cave surface is at a constant temperature of 15.5 °c. the cave is constantly exposed to wind such that 15.5 °c air flows through the cave at 4.5 m/s. the kinematic viscosity of the air is 14.66 x 10-6 m2/s and the molecular diffusion coefficient of water vapor in the air is 0.239 x 10-4 m2/s. because the cave diameter is so large, the flow of wind down the length of the cave, in the x direction, can be treated like it is external flow and the cave surface can be approximated as flat where appropriate. calculate the x value, in a) the transition to turbulent flow occurs at rex meters, where the air flow transitions from laminar to turbulent along the inside surface of the cave b) calculate the x value, in meters, where the bulk steady state concentration of water vapor in the air flowing in the cave is 10% of the saturation concentration. assume the air at the surface of the water layer is 100% saturated with water vapor. assume the wind entering the cave contained no moisture before it entered the cave. take into account the transition from laminar to turbulent flow when solving part b