Tag: the turning effect of a force

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Questions Related to the turning effect of a force

Multiple choice physics turning on a pivot the turning effect of a force moment of force or torque turning effect of force couple

While opening a tap with two fingers, the forces applied are  

  1. equal in magnitude

  2. parallel to each other

  3. opposite in direction

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

While opening a tap with two fingers, a couple should be applied which is defined as a pair of parallel equal forces acting in opposite direction about two different axis.

Multiple choice physics turning on a pivot the turning effect of a force moment of force or torque turning effect of force couple

On applying a constant torque on a body-

  1. linear velocity increases

  2. angular velocity changes

  3. it will rotate with constant angular velocity

  4. it will move with constant velocity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A constant torque applied to a rigid body results in constant angular acceleration, which causes the angular velocity to change over time.

Multiple choice physics turning on a pivot the turning effect of a force moment of force or torque turning effect of force couple

It becomes easier to open or close a door turning about its hinges if the force is applied at the:

  1. Two third of the door

  2. Free edge of the door

  3. Middle of the door

  4. Point near the hinges
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Torque acting about any point O         $\tau _o = rF$                 for $sin\theta = 1$

where $r$ is the distance of the application of force from point O.
As  $r$ is maximum when a force is applied at the free end of the door, thus less amount of force is required to produce the same torque. Hence it is easier to open or close the door if force is applied at its free end. 

Multiple choice physics turning on a pivot the turning effect of a force moment of force or torque turning effect of force couple

State whether true or false.
A spanner with a longer handle can tighten nuts and bolts with less effort.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We know, 

Moment of force = Force \times Distance between action point and force applied.
$\therefore T = F \times R$
As, R increases, T also increases.
So, we required to get less effort.