In: Physics
A bus contains a 1500 kg flywheel (a disk that has a 0.55 m radius) and has a total mass of 11000 kg.
m = 1500 kg
r = 0.55 m
mt = 11000 kg
v1 = 19 m/s
v2 = 2.75 m/s
A. Calculate the angular velocity the flywheel must have to contain enough energy to take the bus from rest to a speed of 19 m/s in rad/s, assuming 90.0% of the rotational kinetic energy can be transformed into translational energy.
B. How high a hill can the bus climb with this stored energy and still have a speed of 2.75 m/s at the top of the hill in m?
given :
M = total mass = 11000 kg
m = mass of flywheel = 1500 kg
Radius of flywheel = R = 0.55 m
Rotational KInetic Energy =
Translational Kinetic energy =
A) The translational kinetic energy attained by the bus is from the rotational kinetic energy of the flywheel.
Let I be the moment of inertia of the flywheel and it's value is = .
let be the angular velocity when the kinetic energy of the bus is zero.
In the question given, the 90% of rotational kinetic energy of flywheel is converted into tenslational kinetic energy of the bus and the bus attained linear velocity v = 19m/s.
therefore,
[answer]
B) after climbing a hill of height say h, the speed of bus is still v2 = 2.75 m/s.
Applying conservation of mechanical energy between ground where speed is 19 m/s and the height where speed is 2.75 m/s. :
total final energy = total initial energy
.
The height reachd is 18.01 m when it has speed 2.75m/s. [answer]