Ekassh

University M

## Wall

wrote the 15/07/2012 10:37

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Ekassh hasn't written any article yet## Questions

## 2

Answers#### Why is it much harder to explain the line spectra of polyelectronic atoms and ions than it is to explain the line spectra of hydrogen and hydrogen-like ions?

How are they different?

30/06/2014
## 1

Answers#### "When the speed of a rear-drive car is increasing on a horizontal road the direction of the frictional force on the tires is: "

"A. forward for all tires
B. backward for all tires
C. forward for the front tires and backward for the rear tires
D. backward for the front tires and forward for the rear tires
E. zero"

26/02/2013
## 1

Answers#### "A forward force on the axle accelerates a rolling wheel on a horizontal surface. If the wheel does not slide the frictional force of the surface on the wheel is: "

"A. zero
B. in the forward direction
C. in the backward direction
D. in the upward direction
E. in the downward direction"

26/02/2013
## 1

Answers#### "Two wheels roll side-by-side without sliding, at the same speed. The radius of wheel 2 is twice the radius of wheel 1. The angular velocity of wheel 2 is: "

"A. twice the angular velocity of wheel 1
B. the same as the angular velocity of wheel 1
C. half the angular velocity of wheel 1
D. more than twice the angular velocity of wheel 1
E. less than half the angular velocity of wheel 1"

26/02/2013
## 1

Answers#### "A disk starts from rest and rotates about afixed axis, subject to a constant net torque. The work done by the torque during the second revolution is as the work done during the first revolution. "

"A. the same
B. twice as much
C. half as much
D. four times as much
E. one-fourth as much"

26/02/2013
## 1

Answers#### "A disk starts from rest and rotates around afixed axis, subject to a constant net torque. The work done by the torque during the second 5s is as the work done during thefirst 5s. "

"A. the same
B. twice as much
C. half as much
D. four times as much
E. one-fourth as much"

26/02/2013
## 1

Answers#### "A disk has a rotational inertia of 6.0kg· m2 and a constant angular acceleration of 2.0rad/s2 . If it starts from rest the work done during thefirst 5.0s by the net torque acting on it is: "

"A. 0
B. 30J
C. 60J
D. 300J
E. 600J"

26/02/2013
## 1

Answers#### "A circular saw is powered by a motor. When the saw is used to cut wood, the wood exerts a torque of 0.80N· m on the saw blade. If the blade rotates with a constant angular velocity of 20rad/s the work done on the blade by the motor in 1.0min is: "

"A. 0
B. 480J
C. 960J
D. 1400J
E. 1800J"

26/02/2013
## 1

Answers#### "A disk with a rotational inertia of 5.0kg· m2 and a radius of 0.25m rotates on afixed axis perpendicular to the disk and through its center. A force of 2.0N is applied tangentially to the rim. As the disk turns through half a revolution the work done by the force is: "

"A. 1.6J
B. 2.5J
C. 6.3J
D. 10J
E. 40J"

26/02/2013
## 1

Answers#### "A pulley with a radius of 3.0cm and a rotational inertia of 4.5×10 −3 kg·m2is suspended from the ceiling. A rope passes over it with a 2.0-kg block attached to one end and a 4.0-kg block attached to the other. The rope does not slip on the pulley. At any instant after the blocks start moving, the object with the greatest kinetic energy is: "

"A. the heavier block
B. the lighter block
C. the pulley
D. either block (the two blocks have the same kinetic energy)
E. none (all three objects have the same kinetic energy)"

26/02/2013
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