Answer:
r = 0.491 m
Explanation:
In this case the System is formed by the teacher with the two masses, so the forces during movement are internal and the angular momentum is conserved
Initial.
L₀ = I₀ w₀
Final
Lf = I w
L₀ = Lf
I₀ w₀ = I w
The moment of inertia is
I₀ = m r₀²
I = m r²
Let's replace
m r₀² w₀ = m r² w
r² = r₀² w₀ / w
Angular velocity
w₀ = 10 rpm (2pi rad / 1 rev) (1 min / 60 s) = 1.047 rad / s
w = 32.5 rpm = 3.403 rad / s
Let's calculate
r = √(0.785 1.047 / 3.403)
r = 0.491 m
Work
Explanation:
Energy can do work or bring about change.
Energy is simply the ability to do work. When work is done, changes occur in a body.
- There are different forms of energy and they are all related to work done.
- When work is done on a body, a force causes a change in that body.
- Both potential and kinetic energy are the same as work done.
- Energy is needed to do work.
- Work is done when a body changes energy.
Learn more:
Energy brainly.com/question/5416146
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Answer:
Explanation:
The condition that the sphere completes the loop is that it doesn't fall off at the top. In order to do that, the sphere has to have enough velocity to beat the centripetal acceleration.
The forces acting on the sphere at the top of the loop:
1- Weight of the sphere to the downwards direction.
2- The normal force to the downwards direction.
So Newton's Second Law gives the following equation
At the minimum velocity, which corresponds to minimum height 'h', the normal force is equal to zero. That means, if the sphere moves any less than the minimum velocity, its weight will be greater than the centripetal force, hence it will fall off.
Therefore,
Now, we can use the conservation of energy to find the minimum height.
Explanation:
Momentum before collision:
(2 kg) (4 m/s) + (5 kg) (-3 m/s) = -3 kg m/s
No external forces act on the balls, so momentum is conserved. Therefore, momentum after collision is also -3 kg m/s.
Assume theres no air reaistance. (or else the ball will oppose the motion of the ball, hence decrease the velocity increase)
see if there are any problems!