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:
Apply Newton's second law in the moving direction.
Explanation:

Friction force applies in the opposite direction of motion; as a restriction.
Answer:
An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements.
Explanation:
The tangent looks good.
The curve is a bit crooked, at the 0.9 and 1.
But overall, cool graph.
Answer: the group in an experiment that doesn’t get treatment
Explanation: