Why us an element considered a pure substance
2 answers:
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Answer:
- 2.32
- 0.43
Explanation:
12.0 kv primary voltage
315 kv secondary voltage ( converted voltage ) V1 or Vo
v2 (Vn)= 730 kv new secondary voltage
a) Ratio of turns in 730 kv to turns in 315 kv
=
therefore the ratio of turns = 2.317 ≈ 2.32
B) ratio of the new current output to the old current output for the same power input to the transformer
since the power input is the same
equation 1
Vp = primary voltage, Vo = old secondary voltage, Vn = new secondary voltage, In = new secondary current, Io = old secondary current
therefore equation 1 becomes
= 315 / 730 = 0.43
Answer:
ω = 2.1 rad/sec
Explanation:
- As the rock is moving along with the merry-go-round, in a circular trajectory, there must be an external force, keeping it on track.
- This force, that changes the direction of the rock but not its speed, is the centripetal force, and aims always towards the center of the circle.
- Now, we need to ask ourselves: what supplies this force?
- In this case, the only force acting on the rock that could do it, is the friction force, more precisely, the static friction force.
- We know that this force can be expressed as follows:
where μs = coefficient of static friction between the rock and the merry-
go-round surface = 0.7, and Fn = normal force.
- In this case, as the surface is horizontal, and the rock is not accelerated in the vertical direction, this force in magnitude must be equal to the weight of the rock, as follows:
- Fn = m*g (2)
- This static friction force is just the same as the centripetal force.
- The centripetal force depends on the square of the angular velocity and the radius of the trajectory, as follows:
- Since (1) is equal to (3), replacing (2) in (1) and solving for ω, we get:
- This is the minimum angular velocity that would cause the rock to begin sliding off, due to that if it is larger than this value , the centripetal force will be larger that the static friction force, which will become a kinetic friction force, causing the rock to slide off.