To solve this problem it is only necessary to apply the kinematic equations of angular motion description, for this purpose we know by definition that,
Where,
Angular Displacement
Angular Acceleration
Angular velocity
Initial angular displacement
For this case we have neither angular velocity nor initial angular displacement, then
Re-arrange for 
Replacing our values,
Therefore the ANgular acceleration of the mass is 
Answer:
Option C is the correct answer.
Explanation:
Considering vertical motion of ball:-
Initial velocity, u = 2 m/s
Acceleration , a = 9.81 m/s²
Displacement, s = 40 m
We have equation of motion s= ut + 0.5 at²
Substituting
s= ut + 0.5 at²
40 = 2 x t + 0.5 x 9.81 x t²
4.9t² + 2t - 40 = 0
t = 2.66 s or t = -3.06 s
So, time is 2.66 s.
Option C is the correct answer.
Answer:
Geocentric model of the universe
Explanation:
In the geocentric model of the universe, the earth is the center of the universe. This theory was later replaced by the heliocentric model which places the sun as the center.
This belief was propagated by the ancient Greeks. The geocentric model of the universe was proposed by Ptolemy.
The model suggests that other planetary bodies orbits the earth.
