Physics Rotation

A stone rotates and "curls" in the

• direction of rotation of the throw

• opposite direction of rotation of the throw

• direction the sweeper pushes it

• any direction since it is filled with fluid

How is contact between the coil and circuit maintained in an alternator?

• A split ring commutator connects to each side for half a turn

• It cannot be maintained.

• The alternator can only complete one revolution and must then be rotated in reverse

• Slip rings and brushes allow continuous connection

How can the voltage output from an alternator be doubled?

• Halve the speed of rotation but reverse the direction of rotation

• Double the speed of rotation

• Reverse the direction of rotation

• Use half the number of coils

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-3

The voltage from a dynamo changes as the coil turns. What is the voltage one half turn after the maximum positive output?

• Half the maximum output

• Maximum positive output again

• Zero voltage

• Maximum negative output

How can the voltage output from a dynamo be doubled?

• Reverse the direction of rotation

• Halve the speed of rotation but reverse the direction of rotation

• Double the speed of rotation

• Use half the number of coils

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-3

In a dynamo, what is the function of the split ring commutator?

• It strengthens the magnetic field to make a greater output current for the same rotation speed

• It reverses the connections every half turn, to keep the output current alternating every half turn

• It reverses the coil connections every half turn, to keep the output current in the same direction all the time

• It prevents the coil from overheating

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

What is the anticlockwise moment acting on this crane?

• 80,000Nm

• 100,000Nm

• 120,000Nm

• 140,000Nm

A seesaw is unbalanced with two people of different masses sitting equal distances from the center. Which of the following will result in equilibrium?

• The larger person moving further away from the center.

• Moving the smaller person closer to the center.

• Moving the smaller person further from the center.

• Making the larger person do nothing.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

Two masses of mass 10.0 and 6.0 kg are hung from massless strings at the end of a light rod. The rod is virtually weightless. A pivot (fulcrum) is placed off center and the system is free to rotate. If the 6.0 kg mass is 4.0 m away from the pivot, how far away is the 10.0 kg mass if the system is not rotating?

• 0.42 m

• 2.4 m

• 4.8 m

• 4.2 m

Tags

NGSS.HS-PS2-2

NGSS.HS-PS2-4

What is the moment produced by the 15 N?

• 15 Nm (clockwise)

• 150 Nm (anti - clockwise)

• 1.5 Nm (anti - clockwise)

• 0.15 Nm (clockwise)