प्रकृति में बल Force In Nature || Class 11th Ch 1 Physical World भौतिक जगत L -2 ?By Gopal Sir

Solve the following crossword using the given clues: ACROSS 3. Principle relating to the apparent weight of a body when immersed in water. 6. Pressure caused by the weight of the air 7. Forces that require physical contact between objects 10. The force that exists between two magnets. 11. Unit of force 12. The resistance to movement that occurs when two bodies are in contact 13. The state when aperson does not feel any sensation of weight. DOWN 1. The pull of the earth 2. SI unit of pressure 4. Measure of the amount of matter in a physical body 5. The upward force that a fluid exerts on an object that is immersed in the fluid. 8. The force with which the earth pulls a body towards its centre. 9. Something that tends to cause movement of a body.

Newton's universal law of gravitation is expressed mathematically as F=(Gm_(1)m_(2))/d^(2) Answer the following the question based on this law: (i) what is represented by m_(1),m_(2) and d? (ii) what is G called? (iii) what is the meaning of the world 'universal' in this law? (iv) Gravitational force between any two ordinary objects is really weak. why? (v) why you or your friend sitting near you do not move towards each other due to gravitation force of attraction? (vi) Though gravitational force is the weakest force in nature, yet it is responsible for holding our solar system.why? (vii) will gravitational force of attraction between two bodies change when they are placed same distance apart (i) on earth (ii) on moon? (viii) how will gravitational force change between two bodies when distance between them is halved? (ix) masses of each of two bodies are doubled. how should the distance between them be changed to keep the gravitational force constant?

In a class Seema is 10th from the top and Bablee is 20th from the bottom. Raju is 11 ranks below Seema and 21 ranks above Bablee. How many students are in the class if list includes all the students of the class? 1) 60 2) 61 3) 62 4) Data inadequate 5) None of these

There are two vectors Force vec(A) = (hat(i) + 3 hat(j) - hat(k)) N and Position vec(B) = (hat(i) + 3 hat(j) - hat(k))m that can be used by two students Alia and Varun. Following are the steps following by each of them. Alia : Step 1 : Calculate unit vector of vec(A) by dividing it by its magnitude and get hat(A) = (hat(i) + 3 hat(j) - hat(k))/(sqrt11) Alia : Step 2 : Get a displacement vector of magnitude 10m using hat(A) Displacement vector = (10(hat(i) +3 hat(j) - hat(k))/(sqrt11)) m Varun : Step 1 : Calculate unit vector of vec(B) by dividing vec(B) by its magnitude and get, hat(B) = ((hat(i) + 3 hat(j) - hat(k))/(sqrt11)) Varun : Step 2 : Get a force vector of magnitude 10 N by using vec(B) Force vector = (10(hat(i) + 3 hat(j) - hat(k)) N)/(sqrt11) Siddharth, a third student, comes and says when we divide or multiply a vector by a scalar, then the physical quantity represented by the vector from a displacement vector from a force vector or a force vector from a displacement vector as calculated by Alia and Varun repectivley. Who is/are correct ?