A 0.74-m diameter solid sphere can be rotated about an axis through its center by a torque of 10.8 m*N which accelerates it uniformly from rest through a total of 160 revolutions in 14.0 s.
1. What is the mass of the sphere?

Respuesta :

Answer:

Mass of the sphere is 19.2 kg

Explanation:

We have given diameter of the sphere d = 0.74 m

So radius r = 0.37 m

Initial angular velocity [tex]\omega _i=0rad/sec[/tex]

Time t = 14 sec

Angular displacement [tex]\Theta =160revolution=160\times 2\pi =1004.8rad[/tex]

From second equation of motion

[tex]\Theta =\omega _it+\frac{1}{2}\alpha t^2[/tex]

So [tex]1004.8=0\times t+\frac{1}{2}\times \alpha \times 14^2[/tex]

[tex]\alpha =10.25rad/sec^2[/tex]

Torque is given [tex]\tau =10.8Nm[/tex]

Torque is equal to [tex]\tau =I\alpha[/tex], here I is moment of inertia and [tex]\alpha[/tex] angular acceleration

So [tex]10.8=10.25\times I[/tex]

[tex]I=1.053kgm^2[/tex]

Moment of inertia of sphere is equal to [tex]I=\frac{2}{5}Mr^2[/tex]

So [tex]1.053=\frac{2}{5}\times M\times 0.37^2[/tex]

M = 19.23 kg

So mass of the sphere is 19.23 kg