Question

A uniform rod weights 20kg and with a load 1kg to one end it balances on a knife edge at 2m from that end the lengths of rod is

Answer 1

Answer:

Step-by-step explanation:10×3=20(L/2 -3)

L=9

Answer 2

The length of the rod is 4.04 meters.

Step-by-step explanation:

The net moment at point P is zero, thus we need to take clockwise direction positive.

(20 (L - x) × (L - x)/2) - x - (20x × x/2) = 0

10 (L - x)² - x - 10 x² = 0

The knife edge is at 2 m. Thus, x = 2.

10 (L - 2)² - 2 - 40 = 0

10 (L - 2)² - 42 = 0

10 (L - 2)² = 42

(L - 2)² = 42/10 = 4.2

L - 2 = √(4.2)

L = 2 + √(4.2)

∴ L = 4.04 m