Answer:A
Explanation:
Given
Two ponies are at Extreme end of turntable with mass m
suppose turntable is moving with angular velocity
Moment of inertia of Turntable and two ponies
let say at any time t they are at a distance of r from center such
Moment of inertia at that instant
conserving angular momentum as net Torque is zero
Thus we can say that angular velocity increases as they move towards each other.
Answer:
a) 4.9 N/m
b) 1.4 m/s
c) 0.225 s
Explanation:
Hooke's law states that
F = k * Δx
Where
F: force applied to a spring
k: constant of the spring
Δx: elongation of the spring
The force applied in this case is the weight of the ball, this is
P = m * g = 0.1 kg * 9.81 m/s^2 = 0.981 N
Rearrainging Hooke's law:
k = F / Δx
k = 0.981 / 0.2 = 4.9 N/m
If the ball is pulled down the spring will acquire some potential energy, when it is released, the potential energy will be released as kinetic energy on the ball
Elastic potential energy is:
The energy gained from the 0.2m pull will be turned into kinetic energy
Ec = U
Therefore:
Rearranging:
After being released the ball will oscillate at the natural frequency of the system, which is
And the period will be:
The period in this case is:
The ball will move up and down taking T time to complete a cycle, the movement from the stretched position to the equilibrium position takes T/4 = 0.225 s