Question

A weightless thread can bear tension upto 3.7 kg wt. A stone of mass 500 gms is tied to it and revolved in a circular path of radius 4 m in a vertical plane. If $g = 10 \mathrm {~ms} ^ { - 2 }$ , then the maximum angular velocity of the stone will be

• A. 4 radians/sec
• B. 16 radians/sec
• C. $\sqrt { 21 }$ radians/sec
• D. 2 radians/sec

Answer 1

Answer: (A)

4 radians/sec

Answer 2

Max. tension that string can bear

= 3.7 kgwt = 37N

Tension at lowest point of vertical loop

$= \mathrm { mg } + \mathrm { m } \omega ^ { 2 } \mathrm { r }$

= $0.5 \times 10 + 0.5 \times \omega ^ { 2 } \times 4 = 5 + 2 \omega ^ { 2 }$

∴ 37 = 5 + 2ω² ⇒ ω = 4 rad/s