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#### Laws of Motion Two Marks Questions

11th Standard

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Physics

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. A spider of mass 50 g is hanging on a string of a cob web. What is the tension in the string?

2. The physics books are stacked on each other in the sequence: +1 volumes 1 and 2; +2 volumes 1 and 2 on a table
a) Identify the forces acting on each book and draw the free body diagram.
b) Identify the forces exerted by each book on the other

3. Apply Lami's theorem on sling shot and calculate the tension in each string?

4. People often say "For every action there is an equivalent opposite reaction". Here they meant 'action of a human'. Is it correct to apply Newton's third law to human actions? What is mean by 'action' in Newton third law? Give your arguments based on Newton's laws.

5. How to verify Newton's third law, using spring balances?

6. Find the acceleration when multiple forces act on the body?

7. "Force and motion are in the' opposite direction". Give example.

8. Prove that second derivative of position vector is not zero, then there must be a force on the body.

9. What is the angle of friction between two surfaces in contact if the coefficient of friction $\frac { 1 }{ \sqrt { 3 } }$?

10. It is easier to roll a barrel than to pull it along the road. Why?

11. A ball of mass 150g moving with a velocity of 1s ms-1 is brought to rest by a player in 0.05s. Calculate the impulse and the average force exerted by the player.

12. A force $\vec { F } =(6\hat { i } -8\hat { j } +10\hat { k } )$ N produces acceleration of 1 m/s2 in a body. Calculate the mass of the body.

13. The position of the particle is represented by y=ut-$\frac { 1 }{ 2 }$gt2
(a) What is the force acting on the particle?
(b) What is the momentum of the particle?

14. Calculate the centripetal acceleration of the Earth which orbits around the Sun. The Sun to Earth distance is approximately 150 million km. (Assume the orbit of Earth to be circular).

15. Consider two objects of masses 5 kg and 20 kg which are initially at rest. A force 100 N is applied on the two objects for 5 second.
(a) What is the momentum gained by each object after 5s?
(b) What is the speed gained by each object after 5s?