Two mechanics worked on a car. The first mechanic charged $ 95 per hour, and the second mechanic charged $ 75 per hour. The mechanics worked for a combined total of 20 hours, and together they charged a total of $ 1800 . How long did each mechanic work?

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero

Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.