Question

33. What is the mass of the rock shown inthe figure?uGuess0cm25cm50cm75cm100cmm=?1 kg)

Answer 1

2 kg

Step-by-step explanation

to maintain the system in equilibrium the sum of momentums(or torques) in The point of contatc must be equal to zero,so

`M_1+M_2=0`

the torque(M) is given by

`M=\text{force}\cdot\text{distance}`

so for M1

`\begin{gathered} M1=\text{force}\cdot\text{distance} \\ \text{force}=\text{ mass }\cdot gravity \\ F=m_1g \\ dis\tan ce=50-25=25\text{ cm=0.25 m} \\ so,\text{ replace} \\ M1=m_1g\cdot0.25\text{ } \\ M1=0.25m_1g \end{gathered}`

and M2 must be equal, so

now, as M1= M2

set equal and solve for m

`\begin{gathered} M1=M2 \\ 0.25m_1g=0.5g \\ \text{divide both sides by 0.25 g} \\ (0.25m_1g)/(0.25g)=(0.5g)/(0.25g) \\ m_1=2\text{ kg} \end{gathered}`

therefore, the mass of the rock is 2 kg