transformer makes use of mutual induction for its operation in which change in magnetic field in one coil due to variation of current , induces voltage in the other coil. so changing magnetic field in the primary coil is very much needed for the transformer. Alternating current is a current which varies with time , hence it is suitable to produce changing magnetic field in the primary coil. on the other hand , the direct current remains constant all the time. hence can not produce a changing magnetic field. so DC current is not useful for transformers.
Answer:
The length of the object would shrink to zero which is not possible.
Explanation:
A rocket or any body cannot reach the speed of light because according to theory of relativity the and the Lorentz factor the length of the object would shrink to zero and the time dilation for that body would be infinite.
The Lorentz factor is given as:
where:
v = speed of the moving object
c = speed of light
Answer:
Explanation:
The answer is D- The number of flies decreased, then leveled off.
Answer:
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A circle has a revolution of 360°. Since there are 12 hour markings, each hour interval has an angle of 30°. In radians, that would be equal to π/6 radians. So, in every 1 hour that passes, it covers π/6 of an angle. So, the angular velocity denoted as ω is π/6 ÷ 1 hour = π/6 rad/h. We can compute the average linear velocity, v, from the relationship:
v = rω, where r is the radius of the circle which is the length of the hour hand
v = (2.4 cm)(π/6 rad/h)
v = 1.257 cm/hour
Therefore, the average velocity is 1.257 cm per hour.
For the average acceleration, it is equal to zero. The hands of the clock move at a constant velocity. Since acceleration is the change of velocity per unit time, there is no change of velocity because it's constant. That's why it is zero.
