Answer:
Final angular velocity is 35rpm
Explanation:
Angular velocity is given by the equation:
I1w1i + I2w2i = I1w1f -I2w2f
But the two disks are identical, so Ii =I2
wf can be calculated using
wf = w1i - w2i/2
Given: w1i =50rpm w2i= 30rpm
wf= (50 + 20) / 2
wf= 70/2 = 35rpm
Answer:
B: It is moving north.
Explanation:
We are told that a train is moving with a velocity of 70 km/h.
Now, we are also told that the positive direction is north.
This means that the train is moving in the northern direction.
We can't say if it is speeding up or not because we are not given the acceleration.
Thus, option B is correct
Answer:
Vi = 24.14 m/s
Explanation:
If we apply Law of Conservation of Energy or Work-Energy Principle here, we get: (neglecting friction)
Loss in K.E of the Rock = Gain in P.E of the Rock
(1/2)(m)(Vi² - Vf²) = mgh
Vi² - Vf² = 2gh
Vi² = Vf² + 2gh
Vi = √(Vf² + 2gh)
where,
Vi = Rock's Speed as it left the ground = ?
Vf = Final Speed = 17 m/s
g = 9.8 m/s²
h = height of rock = 15 m
Therefore,
Vi = √[(17 m/s)² + 2(9.8 m/s²)(15 m)]
Vi = √583 m²/s²
<u>Vi = 24.14 m/s</u>
