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(11 %) Problem 3: A bus contains a 1540 kg flywheel (a disk that has a 0.64 m ra

ID: 2037052 • Letter: #

Question

(11 %) Problem 3: A bus contains a 1540 kg flywheel (a disk that has a 0.64 m radius) and has a total mass of 10600 kg Randomized Variables m- 1540 kg r 0.64 m m, 10600 kg vi = 19 m/s v2 = 3.2 m/s 50% Part (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 900% of the rotational kinetic energy can be transformed into translational energy Grade Summary Deductions Potential ?= 100% tan() | ?| ( acosO Submissions sin) cotan asinO coSO Attempts remaining:20 (3% per attempt) detailed view acotan)sinhO cosh)tanh) cotanhO Degrees Radians END DEL CLEAR Submit Hint I give up! Hints: 2%-deduction per hint. Hints remaining: 3 Feedback: 1% deduction per feedback 50% Part (b) How high a hill can the bus climb with this stored energy and still have a speed of 3.2 m/s at the top of the hill in m?

Explanation / Answer

Energy required = 0.5*m*v^2 = 0.5*10600*19^2 = 1913300 J

Rotational Kinetic Energy Needed = 1913300/0.90 = 2125888.89 J

0.5*I*w^2 = 2125888.89

(0.5*0.5*1540*0.64^2)*w^2 = 2125888.89

w = 116.107 rad/sec

B) Total energy = mgh + 0.5*m*v^2

2125888.89 = 10600*9.8*h + 0.5*10600*3.2^2

h = 19.94 m