Knowing a .02 in gap exists when the temperature is 75 degrees f, determine

(a) the temperature at which the normal stress in the aluminum bar will be equal to -11ksi,
(b) the corresponding exact length of the aluminum bar.

bronze aluminum
a = 2.4 in^2 a=2.8 in^2
e=15x10^6 psi e=10.6x10^6
alph=12x10^-6/f alpha=12.9x^-6/f
l=14in l=18in

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.