(A) 
The energy stored by the system is given by
where
P is the power provided
t is the time elapsed
In this case, we have
P = 60 kW = 60,000 W is the power
t = 7 is the time
Therefore, the energy stored by the system is
(B) 4830 rad/s
The rotational energy of the wheel is given by
(1)
where
is the moment of inertia
is the angular velocity
The moment of inertia of the wheel is
where M is the mass and R the radius of the wheel.
We also know that the energy provided is
So we can rearrange eq.(1) to find the angular velocity:
(C) 
The centripetal acceleration of a point on the edge is given by
where
is the angular velocity
R = 0.12 m is the radius of the wheel
Substituting, we find
Our solar system formed from a huge cloud of dust and gas called a
c. solar nebula
Based on the nebular hypothesis, our solar system formed from hydrogen gas and interstellar dust. The gas and the dust contracted and formed the early stage of the sun.
Force=tension-fg sin ∅
=140-mg sin 18.5
=140-124.35
=15.62N
a=f/m=15.62/40=0.39
now,
v²=u²+2as
=2×0.39×80
v²=62.4
v=7.8m/s
Answer:
i think its 4 or 35
Explanation:
its in the middle of 40 and 30
The whistle you use to call has a frequency of 21 kHz, so you do not recognize it also because your threshold of hearing is only 20 kHz. Since you are unable to hear sounds above this value, you request your friend to blow the whistle and move farther away. The frequency will decrease due to Doppler effect.
