Available Answers

1. 1.

   Write true or false tor each statement:

   1. Two trains going in opposite directions with the same speed are at rest relative to each other.
   2. A ball is thrown vertically upwards. Its motion is uniform throughout.
   3. The motion of a train starting from one station and reaching at another station is non-uniform.
   4. A motion which repeats itself after a fixed​​​​​​​ interval of time is called periodic motion.
   5. A ball thrown by a boy from a roof-top has oscillatory motion.
   6. Mass has both magnitude and direction.
   7. Weight always acts vertically downwards.
   8. Mass varies from place to place but weight does not.
2. 2.

   Fill in the blanks:

   1. Two boys cycling on the road with the same speed are ______________ relative to each other.
   2. The motion in a ______________ is rectilinear​​​​​​​ motion.
   3. One to and fro motion of a clock pendulum takes time = ______________.
   4. 36 km h^-1 = ______________ m s^-1.
   5. Total distance travelled = ______________ x total time taken.
   6. The weight of a girl is 36 kgf. Her mass will be ______________.
   7. The weight of a body is measured using ______________.
3. 3.

   Match the following:

   Column A	Column B
   Circular motion Periodic motion Vibratory motion Rotatory motion Non uniform motion	a running fan  a car moving in a market  revolution of earth around the sun  motion of wire of a guitar motion of pendulum of a clock

4. 4.

   Select the correct alternative:

   1. A book lying on a table is an example of:
   2. The motion of a pendulum is:
   3. A car moving on a straight road is an example of:
   4. A ball falls down vertically. Its motion is:
   5. If a body covers equal distances in equal intervals of time, the motion is said to be:
   6. A boy goes from his house to school by bus at a speed of 20 km h^-1 and returns back
      through the same route at a speed of 30 km h^-1. The average speed of his journey is:
   7. The earth attracts a body of mass 1 kg with a force of 10 N. The mass of a boy is 50 kg. His weight will be:
5. 5.

   Explain the meaning of the terms rest and motion.

6. 6.

   Comment on the statement 'rest and motion are relative terms'. Give an example.