#### Important 3 mark questions

11th Standard

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Physics

Use blue pen Only

Time : 01:00:00 Hrs
Total Marks : 30

9 x 3 = 27
1. A physical quantity x is given by x =${a^2b^3\over c\sqrt{d}}$ .If the percentage errors of measurement in a,b, c and d are  4%, 2%, 3% and 1% respectively, then calculate the percentage error in the calculation of x.

2. The length of a rod as measured in an experiment was found to be 2.48 m, 2.46 m, 2.49 m, 2,50 m and 2.48 m. Find the average length, absolute error and percentage error. Express the result with error limit.

3. If the resultant of two equal forces is $\sqrt{3}$ times a single force, find the angle between the forces.

4. List and explain any two application of angle of repose.

5. A bob is pulled sideways so that string becomes parallel to horizontal and released. Length of the pendulum is 2 m. If due to air resistance loss of energy is 10%, what is the speed with which the bob arrived at the lowest point?

6. A gun fires 8 bullets per second into a target X. If the mass of each bullet is 3 g and its speed 600 s-1. Then, calculate the power delivered by the bullets.

7. Find out the center of mass for the given geometrical structures.
(a) Equilateral triangle
(b) Cylinder
(c) Square

8. Write an expression for mechanical advantage.

9. State Newton’s Universal law of gravitation.

10. A block of mass m is pushed momentarily along a horizontal surface with an initial velocity u. If uk is the coefficient of kinetic friction between the object and surface, find the time at which the block comes to rest.