During a football game, a receiver has just caught a pass and is standing still. Before he can move, a tackler, running at a vel
1 answer:
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(a)
<u>Explanation:</u>
Given:
Moment of Inertia of m₁ about the axis, I₁ = m₁x²
Moment of Inertia of m₂ about the axis. I₂ = m₂ (L - x)²
Kinetic energy is rotational.
Total kinetic energy is
Work done is change in kinetic energy.
To minimize E, differentiate wrt x and equate to zero.
Alternatively, work done is minimum when the axis passes through the center of mass.
Center of mass is at
Answer:
its potential energy decreases and its electric potential decreases.
Explanation:
Let's consider a radial field for simplicity. We have:
- The electric potential of the field is given by:
where
k is the Coulomb's constant
Q is the charge source of the field
r is the distance from Q
We see that the electric potential decreases as we move away from the source. If we consider a positive charge q moving in the direction of the electric field, this charge q will move away from the charge Q (because the field lines generated by the positive particle Q point away from the particle), so the electric potential will decrease.
- The potential energy of the moving charge is given by
where q is the magnitude of the charge. As we said previously, V is decreasing while the charge is moving in the direction of the field, so since U is directly proportional to V, U will decrease as well.