Question

A pulley in the form of solid disc of mass 5kg and radius 1 m is rotating at an angular speed of 120 rpm when the motor is turned off, Neglecting the friction at the axle, calculate the force that must by applied tangentially to the pulley to bring it to rest in 4 revolutions.

Answer 1

Answer:

Use these information

Explanation:

Answer 2

Answer:

Concept:

The force preventing sliding against one another of solid surfaces, fluid layers, and material components is known as friction. There are various types of friction: Dry friction is a force that prevents two solid surfaces from moving laterally relative to one another while they are in contact. Between two surfaces that are sliding or attempting to slide over one another, there is a force called friction. For instance, friction makes it challenging to push a book down the floor. Friction always moves an object in the direction that is counter to the direction that it is travelling or attempting to move. The frictional force itself is focused in the opposite direction of the object's motion.

Given:

When the engine is off, a solid-disc-shaped pulley with a mass of 5 kg and a radius of 1 m is rotating at 120 rpm without regard for friction at the axle.

Find:

Determine the force that has to be delivered tangentially to the pulley in order to stop it after four rotations.

Answer:

$mass = 5 kg\\radius = 1 m\\60 sec = 120 rpm\\1 sec = 2 round\\w = 2*2\pi$

 $=4\pi rad/sec$

ωf=0

ω=ω$0^{2} -2$$\alpha$θ

θ $=8\pi$

ω$0^{2} =2\alpha 8\pi$

       $=16\pi ^{2}$

$\alpha =\pi rad/sec^{2}$

τ $=I\alpha$

   $=\frac{1}{2}MR^{2} *a\\=\frac{1}{2} *5*1^{2} *\pi$

τ $=\frac{5\pi }{2} Nm$

τ $=F*$⊥ dt

$\frac{5\pi }{2} =F*1m$

$F=2.5\pi N$

Almost every facet of daily life, from sports to the weather to armed conflicts, contains the word "force." But at its core, force is a notion with its roots in physics, where it has a very clear and important meaning. The newton (N), which is equal to kg m/s2, is the accepted unit of force. One of the two physical quantities—along with mass—that influence an object's motion is force. Kinematics, which considers position, velocity, and acceleration when describing the motion of objects in space, introduces the idea of dynamics by including force and mass in the study of motion.

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