Hot exhaust gases leaving a stationary diesel engine at 450°c enter a 15-cm-diameter pipe at an average velocity of 3.6 m/s. the surface temperature of the pipe is 180°c. determine the pipe length if the exhaust gases are to leave the pipe at 250°c after transferring heat to water in a heat recovery unit. use properties of air for exhaust gases.

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.

If football was tossed in air without gravity or friction the ball would go into space

Gotta have a picture ^^

Distance covered, s = 8ft - 4ft = 4 ftinitial velocity, u = 34 ft/sthe acrobat is moving upwards and therefore, a = -g = -9.81 m/s^2 = 32.19 ft/s^2applying equation of motion; s = ut -1/2gt^2then,4 = 34t -1/2*32.19t^24 = 34t - 16.095t^2rearranging; -16.095t^2 + 34t - 4 = 0solving the quadratic equation; t = {-34 +/- sqrt [34^2 - 4(-16.)]}/2(-16.095) = 1.06 +/- 0.93 = 0.13 or 1.99the acrobat will take 0.13 seconds to be at 8 ft above the ground. additionally, once at the maximum height, the acrobat will move down and be at the same spot (that is height) after 1.99 seconds moving down.