Answer:
Explanation:
Moment of inertia of the metal rod pivoted in the middle
= M l² / 12
If the spring is compressed by small distance x twisting the rod by angle θ
restoring force by spring
= k x
moment of torque about axis
= k x l /2
= k θ( l /2 )² ( x / .5 l = θ )
=
moment of torque = moment of inertia of rod x angular acceleration
k θ( l /2 )² = M l² / 12 d²θ/dt²
d²θ/dt² = 3 k/M θ
acceleration = ω² θ
ω² = 3 k/M
ω = √ 3 k / M
Answer:

Explanation:
Given,
mass = 1.41 g = 0.00141 Kg
Electric field,E = 670 N/C.
We know,
Force in charge due to Electric field.
F = E q
And also we know
F = m g
Equating both the equation of motion
m g = E q

Charge of the particle is equal to 
A) the universe is expanding
Every galaxy is moving away from each other - not just us. And the further they are away, the faster they are moving