JEE Main202224 Jun 2022Morning ShiftPhysicsMotion in Two DimensionsActual
A boy ties a stone of mass 100 g to the end of a 2 m long string and whirls it around in a horizontal plane. The string can withstand the maximum tension of 80 N . If the maximum speed with which the stone can revolve is K π rev min - 1 . The value of K is : (Assume the string is massless and un-stretchable)
Options
- A400
- B300
- C600
- D800
Correct answer
C. 600
Step-by-step solution
The maximum angular velocity of the stone is ω = r p m × 2 π 60 = K 30   rad   s - 1 The tension in the string will provide the required centripetal force. Therefore, T = m ω 2 l ⇒ 80 = 0 . 1 × K 30 2 × 2 ⇒ K 2 = 360000 ⇒ K = 600