Since power = work done/time, 60= work done/120, work done = 120*60 = 7200. So,work done = 7200N (Newton).
I'm not sure if you're supposed to convert the seconds to time.
Answer:
a)30.14 rad/s2
b)43.5 rad/s
c)60633 J
d)42 kW
e)84 kW
Explanation:
If we treat the propeller is a slender rod, then its moments of inertia is

a. The angular acceleration is Torque divided by moments of inertia:

b. 5 revolution would be equals to
rad, or 31.4 rad. Since the engine just got started


c. Work done during the first 5 revolution would be torque times angular displacement:

d. The time it takes to spin the first 5 revolutions is

The average power output is work per unit time
or 42 kW
e.The instantaneous power at the instant of 5 rev would be Torque times angular speed at that time:
or 84 kW
When an object is dropped, tossed, or kicked, as long as it is not laying on the ground, it accelerates downward, because of the force of gravity acting on it.