Question

A centimeter ruler, balanced at its center point, has two coins placed on it, as shown in the figure. (Figure 1)One coin, of mass M1=10g, is placed at the zero mark; the other, of unknown mass M2, is placed at the 4.7 cm

Does the pivot point (i.e., the triangle in the diagram upon which the ruler balances) exert a force on the ruler? Does it exert a nonzero torque about the pivot?

Find the mass M2. The center of the ruler is at the 3.0 cm. The ruler is in equilibrium; it is perfectly balanced.

Answer 1

M2= 17.6kg or 18Kg with sigfigs

Step-by-step explanation:

What we know:

The Net Torque is balanced therefore equals 0

M1*r1=M2*r2

M1=10g

r1=3cm

M2= unknown

r2=4.7

Math:

M1*r1=M2*r2

10g(3cm-0cm)=M2(4.7cm-3cm)

30=M2(1.7cm)

M2=30/1.7

M2=17.6Kg (18kg w/ sigfigs)