A metre rule is found to balance horizontally at the 48cm mark. When a body of mass 60g is suspended at the 6cm mark the balance point shifts to the 30cm mark. The mass of the metre rule is?
60 g * (30 cm - 6 cm) = m * (48 cm - 30 cm)
yes
To solve this problem, we need to use the principle of moments. The principle of moments states that the sum of the clockwise moments about a pivot point is equal to the sum of the anticlockwise moments about the same pivot point.
Let's denote the mass of the meter rule as M.
When the meter rule is balanced at the 48cm mark horizontally, we can assume that the pivot point is at the 48cm mark. The clockwise moment (M1) is equal to the anticlockwise moment (M2).
Since the body of mass 60g is suspended at the 6cm mark, the clockwise moment due to the body (M1) is given by:
M1 = (60g) * (42cm)
Similarly, the anticlockwise moment due to the meter rule (M2) can be calculated as:
M2 = (M) * (18cm)
Since M1 = M2, we can set up the equation:
(60g) * (42cm) = (M) * (18cm)
Now we can solve for M:
M = (60g * 42cm) / 18cm
Simplifying the expression:
M = (2520gcm) / 18cm
M = 140g
Therefore, the mass of the meter rule is 140g.