## Class XI Physics Important Questions

12/18/2011 CBSE

1. Write the dimensions of x and y in the equation.

F = mx + Y  where
F = Force, m = mass and t = time.

t

2. An object dropped by a person in a lift
remains at the same position relative to the lift and the person. What can you
say about the motion of the lift.

3. If two forces 3 Nand 9 N are acting on a body of mass 12 kg,
draw a diagram to illustrate what orientation of the two forces will produce the
least acceleration and

calculate the acceleration.

4. Two bodies of different masses have same momentum. Which one
will have greater kinetic energy the lighter one or the heavier one. Justify.

5. State the theorem of perpendicular axes of moment of inertia.

6. Write the two essential conditions for a given oscillatory motion to be
SHM.

7. What are beats? How are they produced?

8. Draw a graph showing the variation of amplitude with
frequency for a forced

oscillation and hence define resonance.

10 Define relative velocity. A boy wishes 10 swim across a river
In the shortest possible time? At what angle should he swim

if
the river is flowing with a velocity 10 m/s and

the boy can swim at 5 m/s.

11. A fighter plane is flying horizontally at an altitude of 1
km at a speed of 200 km/h. At what horizontal distance from a target should it
release a bomb so as to hit the

target. Take 9 = 10
m/s
2

11a. Calculate the angle of projection for which the horizontal
range is equal to the

maximum height attained.

12. a. Explain why does a person run a little. while getting
down from a moving bus.

b. Why is it advised to bend knees
while landing on floor after jumping from a height.

13. Show

that

work done in increasing the speed of a body
is equal to the change in  Kinetic Energy produced.