An astronaut uses a jet pack in order to navigate around the exterior of the space station. If the jet pack exerts a thrust force of 25 N and the astronaut has a mass of 75 kg, with suit and jet pack on, what is the
acceleration of the astronaut?
A. 30 m/s
B. 10 m/s
C. 3 m/s
D. 0.33 m/s

Asteel tube (k=50 w/mk) of inner and outer diameter di = 20mm and do=26mm, respectively, is used to transfer heat from hot gases flowing over the tube (h-hot = 200w/m2k) to cold water flowing through the tube (h-cold = 8000 w/m2k). what is the cold-side overall heat transfer coefficient uc? to enhance heat transfer 16 straight fins of rectangular profile are installed longitudinally along the outer surface of the tube. the fins are equally spaced around the circumference of the tube, each having a thickness of 2mm and a length of 15mm. what is the corresponding overall heat transfer coefficient uc? *solve for uc in both cases*