# mechanical engineering

### Dynamics

1- A car is driving up a 10° slope. The engine of the 3500 llbbff car is generating a constant

power of 50 hpp while the car is travelling a constant speed. If the engine is operating at 80%

efficiency, determine the speed of the car neglecting drag and rolling resistance.

2- An elevator and load have a total mass

of 1600 kg. It is balanced by a

counterweight with a mass of 300 kg.

At a given instant, the hoist has an

upward velocity of 2 mm/ss and an

acceleration of 1.5 mm/ss2. Determine

a. The power output from the motor.

b. If the motor has an efficiency of

εε = 0.80, what is the power

generated by the motor?

3- The roller coaster car has a mass of 800 kg including its passenger and start from the top of a

hill with a speed of vv0 = 3 m/s. Determine the minimum height H of the hill so that the car

travels around the loop without leaving the track. The distance from A to B is 10 m. Neglect

friction , mass of the wheels, and the size of the car.

4- A 180 lbf man bungee jumps off a bridge with an initial downward speed of 6 ft/s . The

bridge is 450 f above the surface of the water and the stiffness of the cord is 100 ibf/f.

Determine the length of cord to which he is attached in order to stop momentarily above the

surface of the water.

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