Question

A uniform rod of length 50cm and mass 0.2kg is placed on a fulcrum at a distance of 40cm from the left end of the rod. At what distance from the left end of the rod should a 0.6kg mass be hung to balance the rod?

a.48 cm
b. 50 cm
c. 45 cm
d. the rod can not be balanced with this mass.
e.42 cm
show your work. NO LINKS. ​

Answer 1

x = 45 cm

Step-by-step explanation:

Given that,

The length of a rod, L = 50 cm

Mass, m₁ = 0.2 kg

It is at 40cm from the left end of the rod.

We need to find the distance from the left end of the rod should a 0.6kg mass be hung to balance the rod.

The centre of mass of the rod is at 25 cm.

Taking moments of both masses such that,

`15* 0.2=x* 0.6\\\\x=\drac{3}{0.6}\\\\x=5\ cm`

The distance from the left end is 40+5 = 45 cm.

Hence, at a distance of 45 cm from the left end it will balance the rod.