Discuss the meaning of reverse swirl in reaction hydroturbines, and explain why some reverse swirl may be desirable. Use an equation to support your answer. Why is it not wise to have too much reverse swirl?

This question is about Hohmann transfer orbits. One possible method to terraform the planet Mars is to increase it's water content. This could be achieved by changing the orbits of icy asteroids in the asteroid belt so that they hit Mars and deliver their water to the planet. (a) Assuming an initially circular orbit for an asteroid with an orbital radius of 2.52A.U. and a circular orbit for Mars of 1.52A.U., calculate the du required for the asteroid to be moved onto a transfer orbit that will bring it to the orbit of Mars. You may find it useful to follow the following steps. (i) Determine the initial orbital velocity of the asteroid. (ii) Determine the eccentricity of the transfer orbit between the two circular or- bits. (iii) Determine the velocity of the transfer orbit at perigee. (iv) Determine the velocity of the transfer orbit at apogee. (v) Determine the change in velocity required to move from a circular orbit to be at apogee for the asteroid.

[1] In the cold climates, water pipes may freeze and burst if proper precautions are not taken. In such an occurrence, the exposed part of a pipe on the ground ruptures, and water shoots up to 34 m. Estimate the gage pressure of water in the pipe.