W=0.5M*V2^2-0.5M*V1^2 = 0.5M(V2^2-V1^2)=
450(9^2-36^2) = -546,750 J.
mg*h = -546,750.
8820h = 546,750.
h = 62. m.
2. W = 450(36^2-9^2) = -546,750 J.
Note: The negative sign means the system is doing the work.
speed limit on freeway is 36 m/s and speed limit on service drive is 9 m/s. Mr. Scotts focus has a mass of 900 kg. Since friction depends on so many factors such as the condition of the vehicle and direction of wind, the civil engineer neglects it.
1. How deep should the freeway be so that a car that is going the speed limit at the top of the entrance ramp will be going the speed limit when it reaches the bottom (without touching gas pedal)
2. How deep should the freeway be so that a car going the speed limit at the bottom of the exit ramp will be going at the speed limit when it reaches the top?
3. Compare the results for the exit and entrance ramps. Which height is better in general?
4. the freeway will be used for both mini coopers and mack trucks. how will the different masses effect ones choice of an ideal depth for the freeway?
1 answer
1 answer