IB Physics Rotation

As shown above, a rod with a length L is free to rotate about point A. An external force F is applied perpendicular to the rod. In which of the following cases is the torque on the rod the same as the above?

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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-PS2-4

1. Which of the following must be true for the system of two concentric massless pulleys and two masses shown in the picture for the system to be at equilibrium?

• m₁ = m₂

• m₁R₁ = m₂R₂

• m₁R₂ = m₂R₁

• m₁R₁² = m₂R₂²

Two wheels are fixed to each other and are free to rotate about a frictionless axis through their concentric centers. Four forces are exerted tangentially to the wheels. The magnitude of the net torque is:

• zero

• FR

• 2FR

• 4FR

Two wheels are fixed to each other and are free to rotate about a frictionless axis through their concentric centers. Four forces are exerted tangentially to the wheels. As a result of the net torque on the wheels, the wheels will rotate-

• clockwise

• counterclockwise

Where should another 4 N force be applied to maximize the net torque on the object?

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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.HS-PS2-1

You apply force to a wrench to tighten a bolt. The wrench breaks in half. Select the best answer for what happens next. Assume the force applied remains constant.

• The torque is now half of what it was, because torque and distance are inversely proportional
• The torque is now half of what it was, because torque and distance are directly proportional
• The torque is now double of what it was, because torque and distance are inversely proportional
• The torque is now double of what it was, because torque and distance are directly proportional

When an object is experiencing a net torque

• it is in dynamic equilibrium.
• it is in static equilibrium.
• it is rotating.
• it is translating.

Where will be the centre of gravity of a uniform rod lies ?

• At its end

• At its middle point

• At its centre of its cross sectional area

• Depends upon its material