Firts year physics past paper lahore board 2016 important questions

ACADEMY FOR EXCELLENCE

 Physics   1^st year                   Time=30min                          Total no.20

Q.NO1: Select best one answer.

1. The terminal velocity of a body falling through a fluid

          (a) increases with increasing mass  (b) decreases with increasing mass

          (c) is independent of its mass                  (d) is independent of its size

2. A fluid is said to be ideal if it satisfies the following conditions

(a)          is non-viscous                      (b)   is non-viscous and in-compressible

          (c)      is non-viscous, incompressible and has steady flow

          (d)      has steady flow and is non-viscous

3. In a steady flow of water through a pipe of non-uniform bore, its velocity at a thicker area of cross-section 0.25 m2 is 2 ms-1. At thinner cross-section of half of this area, its speed is

          (a) 1 ms-1              (b) 2 ms-1              (c) 4 ms-1               (d) 8 ms-1

4.  for which body position, will the systolic blood pressure have the least value in the body?

          (a) Standing up right           (b) Sitting relaxed    

          (c) Lying horizontally           (d) Standing on one's head

5. Torricelli’s theorem states that

          (a)                             (b)

          (c)                       (d)

Q#2.Short Questions

1.   Write the properties of ideal fluids.

2.   Define Equation of Continuity.

3.   Describe lifting of an aero plane.

4.    Define Terminal velocity and Drag force.

Q#3.Long Questions

1.   Write a note on Bernoulli’s equations.

2.   An airplane design calls for a lift due to the net force of the moving air on the wing of about 1000Nm^-2 of wing area. Assume that air flows past the wing of an air craft with stream line flow. If the speed of flow past the lower wing surface is 160 ms^-1 ? The density of air is 1.29 kgm-3 and assume maximum thickness of wing be one meter.