With constant angular acceleration 
, the disk achieves an angular velocity 
at time 
according to
and angular displacement 
according to
a. So after 1.00 s, having rotated 21.0 rad, it must have undergone an acceleration of
b. Under constant acceleration, the average angular velocity is equivalent to
where 
and 
are the final and initial angular velocities, respectively. Then
c. After 1.00 s, the disk has instantaneous angular velocity
d. During the next 1.00 s, the disk will start moving with the angular velocity 
equal to the one found in part (c). Ignoring the 21.0 rad it had rotated in the first 1.00 s interval, the disk will rotate by angle according to
which would be equal to
The work W done by the electric field in moving the proton is equal to the difference in electric potential energy of the proton between its initial location and its final location, therefore:
where q is the charge of the proton,
, with
being the elementary charge, and
and
are the initial and final voltage.
Substituting, we get (in electronvolts):
and in Joule:
The hotter star will be 16 times more luminous - luminosity depends on two things - the size of the star and the temperature of the star. The hotter a star is, the more energy it will give out. This will give rise to greater luminosity.
To solve this problem it is necessary to apply the concepts related to Newton's second Law and the force of friction. According to Newton, the Force is defined as
F = ma
Where,
m= Mass
a = Acceleration
At the same time the frictional force can be defined as,
Where,
Frictional coefficient
N = Normal force (mass*gravity)
Our values are given as,
By condition of Balance the friction force must be equal to the total net force, that is to say
Re-arrange to find acceleration,
Therefore the acceleration the horse can give is 
