A 20 kg child is sliding at 3 m/s across a frictionless frozen pond a -45 degrees relative to the x-axis, straight towards a dangerous hole in the ice. A physics professor is out for a stroll when he spots the child in peril and heroically launches herself across the ice at 30 degrees relative to the x-axis to intercept the child. Required:
a. If the physics professor weighs 78.9 kg and launches herself across the ice with a velocity of 5 m/s. What is the magnitude of the velocity of the duo after the professor has grabbed the child?
b. At what angle (relative to the +x axis) with the duo be sliding after the rescue? Give an angle in degrees measured counter-clockwise from the x axis.

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i.e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

Which changes of state do the labels represent? a: b: c:

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.