Q19 of 23 Page 117

The bob of a simple pendulum of length 1 m has mass 100g and a speed of 1.4 m/s at the lowest point in its path. Find the tension in the string at this moment.

According to the question;

Length of pendulum (l) = 1 m;


Mass of pendulum (m) = 100g =


Velocity at lowest point (v) = 1.4 m/s.



Now;


The Tension in the string is equal to the sum of force in the circular path (centripetal force) and gravitational force..


⇒ Tension T = Centripetal force + gravitational force.


⇒ T = + mg


⇒ T = + 0.1 × 9.8.


(Length of string(l) = radius of circle in which bob of pendulum moves (r))


⇒ T = 0.196 + 0.98


⇒ T = 1.176 N.


The tension in the string is 1.176 N.


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