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ANEK [815]
2 years ago
8

This is may mastering physics homework and I just need help solving the question.

Physics
1 answer:
laila [671]2 years ago
6 0

Answer:

Angular speed of the disc after he fold his hands is given as

\omega_f = 27.5 rpm

Explanation:

As we know that the moment of inertia of the solid cylinder is given as

I_1 = \frac{m_1r_1^2}{2}

so we have

I_1 = \frac{(950/9.81)(0.20)^2}{2}

I_1 = 1.94 kg m^2

now moment of inertia of two dumbbell in his hand is given as

I_2 = 2(m_2 r_2^2)

I_2 = 2(4)(0.85)^2

I_2 = 5.78 kg m^2

Now moment of inertia of the disc is given as

I_3 = \frac{1}{2}MR^2

I_3 = \frac{1}{2}(1500/9.81)(2^2)

I_3 = 305.8 kg m^2

Now we can use angular momentum conservation as there is no external torque on it

(I_1 + I_2 + I_3) \omega_i = (I_1 + I_3)\omega_f

(1.94 + 5.78 + 305.8) 27 = (1.94 + 305.8) \omega_f

\omega_f = 27.5 rpm

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A boy is trying to roll a bowling ball up a hill, as shown in the image below. If
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The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.

<h3>What is mechanical energy?</h3>

The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.

M.E = KE +PE

A boy is trying to roll a bowling ball up a hill. The friction is ignored.  The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²

The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.

M.E bottom of hill = M.E on top of hill

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At the top of hill, the velocity will become zero. So, final kinetic energy is zero.

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2 years ago
A worker uses a cart to move a load of bricks a distance of 10m across a parking lot. if he pushes the cart with a constant forc
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Answer:

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6 0
3 years ago
Read 2 more answers
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