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Question
A main difference between gravitational and electric forces is that electrical forcesA) attract.
B) repel or attract.
C) obey the inverse-square law.
D) act over shorter distances.
E) are weaker.
Answer
This answer is hidden. It contains 1 characters.
Related questions
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Q:
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C) acts over a longer distance.
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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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Q:
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B) 2,000 kg m/s.
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Q:
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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.
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D) 48 m/s.
E) none of the above
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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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.
D) all of the above
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Q:
The force due to gravity that acts on a block of ice that slides down an icy ramp
A) remains equal to mg at all angles.
B) decreases as the slope of the ramp increases.
C) becomes greatest when the ramp is vertical.
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.
D) her weight.
Q:
When a cannonball is fired from a cannon, which undergoes the greater acceleration?
A) the cannonball
B) the recoiling cannon
C) both the same
Q:
A pair of toy freight cars, one twice the mass of the other, fly apart when a compressed spring that joins them is released. Acceleration will be greater for the
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B) lighter car.
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Q:
The force with which Earth pulls on the Moon is
A) somewhat greater than Moon's pull on Earth.
B) the only force acting between Earth and Moon.
C) equal in magnitude to the force that Moon pulls on Earth.
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:
To produce an acceleration to a system there
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
A) combined weight of the arrow and bowstring.
B) friction of the ground against the archer's feet.
C) grip of the archer's hand on the bow.
D) arrow's push against the bowstring.
Q:
A fast-moving missile soaring overhead possesses
A) speed.
B) force.
C) both of these
D) neither of these