Question

A body of mass 0.4 kg is attached to a string 1.2m long ans then whirled round horizontally making 120 revolution per minute. find angular velocity​

Answer 1

Explanation:

Mass, m=0.2 kg

Radius, r=1 m

Angular speed, ω=90 rpm

⟹ω=

60

90

⟹ω=1.5 rps

⟹ω=3π rad/s

(a) Angular velocity, ω=3π rad/s

(b) Centripetal acceleration. a=rw

2

⟹a=1×3π×3π

⟹a=9π

2

m/s

2

(c) Centripetal Force, F=ma

⟹F=0.2×9π

2

⟹F=1.8π

2

N

(d) Tension in string, = Centripetal Force

⟹T=F=1.8π

2

N

Answer 2

Answer:

w=4 m/s

Explanation:

w=2$\pi$/T

  = 2$\pi$×120/60

  = 4$\pi$