1. V1 = 9000rev/min * 1min/60s * 6.28rad/rev = 942.5 rad/s.
V2 = 5500rev/min * 1min/60s * 6.28rad/rev. = 576 rad/s.
a. a = (V2-V1)/t
1. A small fly wheel fitted to a motor with a moment of inertia of 80 kg m² slows down from 9000 rpm to 5500 rpm in 7.5 seconds.
For the fly wheel, calculate:
• The rate of deceleration which you can assume to be constant
• The braking torque.
2.If the energy used to heat up a block of 2kg of copper is 115.8 kJ, what is the temperature it was heated to if the starting temperature was 100oC and the specific heat capacity is 386 J/kgK.
1 answer
1 answer