PHYSICAL WORLD
1.What is physics
2.How is science and technology related
3.Name the fundamental forces in nature
UNITS AND MEASUREMENT
1.Pick the odd one out from the following:
a. Kilogram b.Second
c. Ampere d. Candela
e. Impulse
2. Classify the following pairs of physical quantities which have the same and
different dimensions
a. Torque and work
b. Linear momentum and angular momentum
c. Specific heat and thermal conductivity
d. Gravitational potential and square of velocity
3. a. Method of dimensions can be used to check the correctness of
equations. Name the principle involved in this.
b. One student doubts the expression for kinetic energy as K.E = MV3 or
K.E = ½ MV2 . How can you help him
c. If the dimensions of [ML-1T-2], test by the method of dimensions the
correctness of the equation δ = Wl3/4bd3y. Here δ is depression at the
middle of a beam of length l ,breadth b and thiockness d.W is the weight
loaded in the middle.
4. Fill in the blanks:
a. 1 micron = …………. M.
b. Hertz is the unit of ……………..
5. a. Relativistic variation of mass with velocity is given by m = m0 / √1 – x2/c2
Where m0 is the rest mass and ‘c’ is the speed of light.What is the
dimensional formula of ‘x’?
b. If the percentage error in the measurement of radius ‘R’ of a sphere is 2% ,
then what is the percentage error in its volume?
6. Mechanical power is represented by P=Fv+Av3 ρ . where F is the force,v is the
velocity ,A is the area and ρ is the density.
a. The dimensional formula of power is ………………………
b. Check the dimensional validity of the above equation.
c. Which of the following equations can’t be obtained by the dimensional method .
i. T = K√l/g
ii. E = Kmv2
iii. P = h ρg
iv. N =N0e-λt
MOTION IN A STRAIGHT LINE
1. A new unit of light is chosen such that the speed of light in vaccum is unity.
Determine the distance between sun and the earth in terms of the new unit if
a ray of light takes 8 minutes and 20 seconds to cover this distance.
2. A balloon is ascending at the rate of 14 m/s and at a height of 98 m above the
ground. A stone is dropped from it.
a. State whether the motion of balloon is accelerated or retarded.
b. After how much time does the stone reaches the ground.
c. Determine the velocity with which the stone strikes the ground.
3. a. State the difference between speed and velocity. Can a body move with
uniform speed but with variable velocity? Explain with the help of an example.
b. Two balls are thrown simultaneously,one vertically upwards from the
ground and the other from a height of 40 m. If both are thrown with same
velocity, at what height from ground will they collide.(Take g =9.8m/s2 )
c. Show that a body thrown vertically upwards returns with the same
magnitude of velocity.
4. Motion is common to everything in universe.It is the change of position of an
object with time.
a. The slope of position time graph of a particle gives
A. acceleration
B. displacement
C. velocity
D. momentum
b. Give example of a body possessing zero velocity and that is still accelerating.
c. A car starts accelerating from rest for some time, moves with a uniform
velocity for sometime and comes to rest with a uniform retardation.Draw the
velocity –time graph of the car.
d. A car covers the first half of the distance between two places at a speed of
40kmph and the second half at 60kmph.Calculate the average speed of the car.
5. a. A ball is thrown vertically upwards from the top of a tower with a velocity v .
Another ball is thrown vertically downwards with the same velocity.Which ball
will hit the ground with greater velocity.
b. A boy drops a ball through the window of a train , which is moving with
uniform velocity. What will be the path of the ball as observed by
i. the same boy sitting in the train?
ii. another boy standing on the platform and
iii. a third boy siting in atrain moving in the opposite direction on a parallel
track?
6.The drver ofa truck moving at a costant speed of 20 m/s sees a car infront of
him at a distance of 110 meters stopping suddenly.Breaks of the truck give an
acceleration of -3m/s2 . What will be the maximum allowable reaction time to
avoid collision and what distance would have the truck moved before stopping
applying the breaks.
MOTION IN A PLANE
7.
a. Define a vector.
b.Find the angle between
c. Determine the value of
8. a. Parallelogram law helps to find the magnitude and direction of the resultant
of two forces.State the law.
b. Two vectors
them.Find the magnitude and direction of the resultant vector
c. What will be the direction of resultant when ѳ =0 and when ѳ = 180 degrees.
d. What will be the angle between two vectors of equal magnitude for their
resultant to have the same magnitude as one of the vectors.
9. a. An object projected into air with a velocity is called projectile.For a
projectile arrive at the equations for the following.
i. Time of flight
ii. Maximum horizontal range.
iii. Maximum height
b. what will be the range when angle of projections are zero degrees and
ninety degrees ?
c. Show that for a projectile , the upward time of flight is equal to down ward
time of flight.
d. At what angles will a projectile have the same range for a velocity
10. A boy throws a cricket ball with a velocity u at an angle ѳ with the horizontal.
a. What is the path followed by the ball .
b. At the highest point what are the vertical and horizontal components of
velocities.
11. a. From the relationship between linear and angular velocities, find the
relation Between linear and angular accelerations.
b.Find the angular velocities of minute and second hands of a clock.
c. A ball trapped in a circular path of radius 10 cm moves steadily and
complete 10 revolutions in 100 sec. What is the angular velocity and what is
the linear velocity of its motion.Is acceleration vector a constant vector.
12. Ramesh observes the motion of an insect. He finds that it travels 6 revolutions
in an anticlockwise direction for a time of 3.14 sec.
a. Find the angular velocity of the insect.
b. If the insect travels 4 revolutions in clockwise direction for 8.6 sec what wil
the angular speed averaged over the total time.
c.Obtain the expression for the centripetal acceleration (ac) in terms of
angular speed (ω)
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