Torq and angular momentum

A child spins a toy top, applying a force to the peg in the middle. The force applied results in a tangential acceleration of the peg. If the radius of the peg is 0.50 cm (0.0050 m), and the tangential acceleration applied is a_tan = 0.540 m/s2, what is the angular acceleration of the top?

• 27 rad/s/s

• 108 rad/s/s

• .009 rad/s/s

• answer not available

A rod is pivoted about its center and initially rotates at 2.0 rad/s. It increases its angular velocity to 14 rad/s in 3.0s. What is its angular acceleration during the 3.0 period?

• 2 rad s/s

• 4 rad s/s

• 6 rad s/s

• 8 rad s/s

A fan spins with a constant angular speed of 500 radians/second. How long will it take to cover an angle of 2π radians (one revolution)?

• 0.013 s
• 0.002 s
• 76.9 s
• 6.28 s

Klyde's angular velocity is

• the same as Bonnie's

• twice Bonnie's

• half of Bonnie's

• 1/4 Bonnie's

Who has the larger linear (tangential) velocity?

• Klyde

• Bonnie

• Same

• both zero

Who has the larger centripetal acceleration?

• Klyde

• Bonnie

• Same

• Both zero

A 800N man is playing on a seesaw with son who has a weight of 200N. If the child is sitting 3 meters away, how far will the man have to sit to balance the seesaw?

• 0.75m
• 3m
• 1.5m
• 1m

Tags

NGSS.MS-PS2-2

In the diagram above, two masses, one with mass m, the other with mass M = 2m are resting on a uniform plank of length L that pivots at its midpoint. If the mass m is at the far end of the plank, how far away from the pivot should the mass M be to balance the plank in a horizontal position shown?

• L/2
• L/3
• L/4
• L/6

Tags

NGSS.MS-PS2-4

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm
• 1.5 Nm
• 750 Nm
• 150 Nm

Tags

NGSS.HS-PS2-1

A uniform rod weighs 40 N and is 1.0 m long. It is hinged to a wall at the left end, and held in a horizontal position at the right end by a vertical string of negligible weight, as shown in the figure. What is the magnitude of the torque due to the string about a horizontal axis that passes through the hinge and is perpendicular to the rod? The hinge is very small with negligible friction.

• 5.0 N ∙ m
• 20 N ∙ m
• 10 N ∙ m
• 40 N ∙ m