Answer:

Explanation:
The density changes means that the length in the direction of the motion is changed.
Therefore,

Given :
Side, b = h = 0.13 m
Mass, m = 3.3 kg
Density = 8100 
So,


l = 0.024 m
Then for relativistic length contraction,







Therefore, the speed of the observer relative to the cube is 0.9833 c (in the units of c).
The correct answer to the question is vertically downward i.e towards the centre of earth.
EXPLANATION:
As per the question, the box is pulled to the right.
Hence, the direction of the applied force is towards right.
We are asked to determine the direction of the gravitational force that acts on the body.
Before answering this question, first we gave to understand the gravitational force of earth.
Any body present on the surface of earth is attracted with the force of gravity of earth ( gravitational force ) towards its centre. It is equivalent to the weight of the body.
The force of gravity is always directed towards the centre of earth irrespective of the nature of applied force.
Hence, the direction of the gravitational force which acts on the box is vertically downward.
Answer:
(a) I=0.01 kg.m²
(b) I=0.03 kg.m²
Explanation:
Given data
Mass of disk M=2.0 kg
Diameter of disk d=20 cm=0.20 m
To Find
(a) Moment of inertia through the center of disk
(b) Moment of inertia through the edge of disk
Solution
For (a) Moment of inertia through the center of disk
Using the equation of moment of Inertia

For (b) Moment of inertia through the edge of disk
We can apply parallel axis theorem for calculating moment of inertia
Answer:
B) PbI2 + 2 KCl
Explanation:
To keep the the law of conservation of matter, the equation given above must be balanced i.e the total element in the reactant must be equal to the total elements in the product.
Given the equation
PbCl2 (aq) + 2 KI (aq) →
At the reactant shown, there are one mole of lead Pb, 2 moles of chlorine Cl, 2moles of Potassium K and 2 moles of Iodine.
During reaction, the Chlorine atom will react with the potassium atom K and the lead atom Pb will react with the iodine atom.
The resulting product that will balance the chemical equation is
PbI2 + 2 KCl
The equation will then become
PbCl2 (aq) + 2 KI (aq) → PbI2 + 2 KCl
If we look at both sides of the equation, we will see that all the elements have the same number of atoms.
Explanation is in this link
https://doubtnut.app/physics-question/when-the-distance-between-two-charged-particles-is-doubled-the-force-between-them-becomes-422318076