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A uniform circular disc of radius 50 cm ...

A uniform circular disc of radius 50 cm at is free to turn about an axis which is perpendicular to its plane and passes through its centre. It is subjected to a torque which produces a constant angular acceleration of `2"rad"s^(-2)`. Its net acceleration is `ms^(-2)` at the end of 2.0 s is approximately.

A

6

B

6

C

8

D

7

Text Solution

Verified by Experts

The correct Answer is:
C
Radius `=r=50 cm =0.5m`
Angular accelerastion `alpha=2 "rad"s^(-2)`
Initial angular velcocity `omega_(0)=0` `=0.5xx2=1ms^(-2)`
`omega=omega_(0)+alphat`
At the end of 2 sec,
`omega=omega_(0)+alphat`
`=0+2xx2=4"rad" s^(-1)`
Radial acceleration
`a_(r)=omega^(2)r`
`a_(4)=(4)^(2)xx0.5=8ms^(-2)`
Net acceleration
`=sqrt(a_(4)^(2)+a_(t)^(2))`
`=sqrt((8)^(2)+(1)^(2))=sqrt(65)`
`=8ms^(-2)`
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