Class XI Physics Revision Assignment

Mechanical Properties of Solids and Fluids

1.       Define elasticity and plasticity. Give examples (2 ) of ideal plastics.                           (3)

2.       What does the slope of stress vs. strain graph give?                                                 (1)

3.       Why are springs made of steel and not copper? Given Y for steel = 200 X 10⁹  N/m²  and Y for copper= 120 X 10⁹ N/m²                                                                                                                   (1)

4.       Why bridges are declared unsafe for use after a long time?                                       (1)

5.       Define elastomers. Draw the stress strain curve for an elastomer.                              (2)

6.       Define (a)Young’s modulus (b)Bulk modulus (c)Modulus of Rigidity. Write mathematical expressions for these moduli.                                                                                                            (3)

7.       What is compressibility?                                                                                           (1)

8.       A cable is replaced by another of the same length and material but of twice the diameter.

(a)    How does this affect its elongation under a given load?

(b)    How many times will be the maximum load it can now support , without exceeding the elastic limit?                                                                                                       (3)

9.       State and prove the Pascal’s law of transmission of fluid pressure.                              (2)

10.   Explain the principle and working of a Hydraulic lift with diagram.                              (3)

11.   State and prove the Bernoulli’s principle for the flow of non- viscous fluids.                (4)

12.   Why still water runs deep?                                                                                        (1)

13.   Why is it dangerous to stand near the edge of the platform when a fast moving train is crossing it?        (1)

14.   Derive Stoke’s law dimensionally. Given that viscous force depends on coefficient of viscosity, radius of the spherical body and velocity of the body.                                                                      (2)

15.   How does Bernoulli’s principle help in explaining heart attack?                                    (2)