Question

(2) An object of mass 100 g move around
circumference of circle of radius 2 m with
constant angular speed 7.5 rad/s. Compute
(a) linear speed
(b) force directed towards centre.​

Answer 1

Given,

An object of mass,m = 100g moves around circumference of circle of radius, r = 2m with constant angular speed, ω = 7.5 rad/s.

To find,

• a) linear speed.
• b) force directed towards centre.

linear speed = angular speed × radius

i.e., v = ωr

⇒v = 7.5 rad/sec × 2m = 15 m/s

therefore linear speed of the object is 15 m/s.

force directed towards the centre , F = mv²/r

= {100 × 10¯³ kg × (15 m/s)²}/(2m)

= (0.1 × 225)/2

= 11.25 N

therefore, force directed towards the centre of the object is 11.25 N