Item 11 Part A The car C and its contents have a weight of 6

Item 11 Part A The car C and its contents have a weight of 620 lb , whereas block B has a weight of 290 lb. The car is released from rest. (Figure 1) Determine the car\'s speed when it travels 30 ft down the 20° incline. Suggestion: To measure the gravitational potential energy, establish separate datums at the initial elevations of B and C Express your answer to three significant figures and include the appropriate units. Value Units u= 1 Value Units Submit My Answers Give Up

Solution

Sol. We have to find the car speed on the slope 20deg.

Step1: Acc. to Energy conservation

K.E+P.E= T.E

Here K.E= Kinectic Energy in m/s

P.E= Potential energy m

now P.E=mgZ (Here Z= distance moved by the block B when a car is traveling down)

now K.E= 1/2*M*V^2

here M= Mass of car V= Velocity or Speed of the car

P.E=290*9.81*Z (In order to find Z we use trignometry )

tan20deg= P/B= Z/30ft so we get Z=0.3639*30=10.91ft

K.E=1/2*620*V^2=290*9.81*10.91

V=9.48lb-ft/s