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Question
If the primary of a transformer is connected to a dc power source, the transformer would have a voltage outputA) at a higher efficiency than with an ac source.
B) the same.
C) that is also dc.
D) only while being connected or disconnected.
E) none of the above
Answer
This answer is hidden. It contains 1 characters.
Related questions
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If the speed of a bicycle is reduced to half before skidding to a stop, it will skid
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B) one-fourth as far.
C) one-half as far.
D) none of the above
Q:
A cannonball has more kinetic energy than the recoiling cannon from which it is fired because the force on the ball
A) is more concentrated.
B) meets less resistance than the cannon on the ground.
C) acts over a longer distance.
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If a Ping-Pong ball and a golf ball both move in the same direction with the same amount of kinetic energy, the speed of the Ping-Pong ball must be
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A) continue along the path as if the explosion didn't occur.
B) cancels to zero by vector addition.
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A golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. The bowling ball is set in motion with a momentum of
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A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact. The boat
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Q:
When you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing. In this way the average force your body experiences is
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Q:
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Q:
It is correct to say that impulse is equal to
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A) 4 kg.
B) 12 kg.
C) 16 kg.
D) 144 kg.
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Q:
The speed of a 4-kg ball with a momentum of 12 kg m/s is
A) 3 m/s.
B) 4 m/s.
C) 12 m/s.
D) 48 m/s.
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Q:
A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is
A) zero.
B) twice.
C) four times as much.
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Q:
A river 100 m wide flows due south at 1 m/s. A boat that goes 1 m/s relative to the water leaves the west bank. To land at a point due east of its starting point, the boat must be pointed
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D) nowhere"it can't be done.
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A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is greater than 90o, their resultant is
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Q:
As the sloped surface supporting a shoe becomes steeper
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B) the normal force becomes less.
C) friction needed to keep it at rest increases.
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The force due to gravity that acts on a block of ice that slides down an icy ramp
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B) decreases as the slope of the ramp increases.
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Q:
When Nellie hangs suspended from a pair of ropes that are not vertical, the tension in each rope is
A) less than half her weight.
B) half her weight.
C) more than half her weight.
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Q:
When a cannonball is fired from a cannon, which undergoes the greater acceleration?
A) the cannonball
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C) both the same
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Q:
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A) somewhat greater than Moon's pull on Earth.
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Q:
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A) air resistance acting against the ball.
B) acceleration of the ball.
C) ball's pull on Earth.
D) none of the above
Q:
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A) must be a net force on the system.
B) may or may not be a net force on the system.
C) must be acceleration outside the system also.
Q:
An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the
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B) friction of the ground against the archer's feet.
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Q:
A fast-moving missile soaring overhead possesses
A) speed.
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