Question

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. (Ans: 1.076N)

Answer 1

Given conditions ⇒

Mass =100 g

=0.10 kg

Velocity (v)=1.4 m/s

Radius(r)=1 m

The Tension in the string at the lowest point will be due to the weight of the bob and circular motion of the bob.

Therefore,

Tension = Force of gravity + Centripetal Force

∴ Tension = mg + mv²/r

∴ T = 0.10 × 10 + 0.10 × (1.4)²/1

⇒ T = 1 + 0.196 N

∴ T = 1.196 N

Hence, the tension in the string at the Instant = 1.196 N.

Hope it helps.