Explanation:
Given that,
Mass if the rock, m = 1 kg
It is suspended from the tip of a horizontal meter stick at the 0-cm mark so that the meter stick barely balances like a seesaw when its fulcrum is at the 12.5-cm mark.
We need to find the mass of the meter stick. The force acting by the stone is
F = 1 × 9.8 = 9.8 N
Let W be the weight of the meter stick. If the net torque is zero on the stick then the stick does not move and it remains in equilibrium condition. So, taking torque about the pivot.

W = 3.266 N
The mass of the meters stick is :

So, the mass of the meter stick is 0.333 kg.
Answer:
Light passes through the gas
Light passes through the pure water
Light passes through some solids
Explanation:
In gasses, there are many spaces between the molecules. These spaces allow light to pass through them without any interruption.
In pure water, there are some spaces between particles. these particles allow some light rays to pass theough, some to move through the common boundary and reflec5 some of them.
in solids, some allow light to pass through as they are transparent or translucent
Answer:
The number of protons in the atom!
Explanation:
<span>Mccarthyism describes a political witchhunt, specifically refers to Sen. McCarthy's cold war era congressional commitees whose aim was to investigate and "out" or reveal individuals with communist "sympathies".</span>
Answer: Teeth is an example of a wedge.
Explanation :
the machines that make our work easier are called simple machines. Some machines can be compound because they are a combination of more than two simple machines. For example, stapler.
Teeth are an example of a wedge. It is a simple machine which consists of two inclined planes. It is used to split apart objects.
The mechanical advantage of a wedge is more than 1.
So, the correct option is (b) " Wedge".