A pulley has a moment of inertial of 0.85kg m about an axle and a radius of 170mm. The string is wrapped around the pulley exerts a constant force of magnitude 32N. Determine the angular acceleration of the pulley. Find the rotational speed of the pulley at t = 2s. How many revolutions did the pulley make during this time?

Respuesta :

Answer:

The no of revolutions is 2.032 revolution.

Explanation:

Given that,

Moment of inertia = 0.85 Kgm²

Radius = 170 mm

Force = 32 N

Time =  2s

We need to calculate the angular acceleration

Using formula of torque

[tex]\tau=I\times\alpha[/tex]

[tex]\alpha=\dfrac{\tau}{I}[/tex]

[tex]\alpha=\dfrac{F\times r}{I}[/tex]

Where, F = force

r = radius

I = moment of inertia

Put the value into the formula

[tex]\alpha=\dfrac{32\times170\times10^{-3}}{0.85}[/tex]

[tex]\alpha=6.4\ m/s^2[/tex]

We need to calculate the rotational speed

Using equation of angular motion

[tex]\omega_{f}=\omega_{i}+\alpha t[/tex]

[tex]\omega_{f}=6.4\times2[/tex]

[tex]\omega=12.8\ rad/s[/tex]

We need to calculate the angular position

Using equation of angular motion

[tex]\theta=\omega_{i}+\dfrac{1}{2}\alpha t^2[/tex]

[tex]\theta=0+\dfrac{1}{2}\times6.4\times4[/tex]

[tex]\theta=12.8\ radian[/tex]

We need to calculate no of revolutions

[tex]n = \dfrac{\theta}{2\pi}[/tex]

[tex]n=\dfrac{12.8}{2\times3.15}[/tex]

[tex]n=2.032\ revolution[/tex]

Hence, The no of revolutions is 2.032 revolution.