Question

A string of length 1m is fixed at one end and carries a mass of 100 g at the other end. The string makes 2/π revolutions per second around the vertical axis through the fixed end. If angle of inclination of the string with the vertical is cos^-15/8, the linear velocity of the mass is nearly

• A. 1 ms^-1
• B. 2 ms^-1
• C. 3 ms^-1
• D. 4 ms^-1

Answer 1

Answer: (C)

3 ms^-1

Answer 2

Using u = rω = r × 2πf

= 1 sin θ × 2πf, we get

( r = 1 sin θ)

u = 1 × 0.78 × 2π × $\frac{2}{\pi}$ = 3.12 ms^-1