Physics Sample Questions for Grade-IX

Class: IX

Subject: Physics

Time: 2.5 hours                                                                                                                         Marks. 40

1.         The house of Mr. Khan is situated 850 m away from bus-stand. Everyday he awakes from sleep with maximum siren. It needs approximately 2.5S to reach the sound of siren to him. Everybody of his house live with environment of loud sound. Oneday old mother of Mr. Khan is attacked by ulcer and Doctor told that loud sound is harmful for human body.

            a)         What is sound?                                                                                                             1

            b)         How loud sound waves propagate in air and reach the ears of Mr. Khan?                                  4

            c)         Describe how can you determine the velocity of sound.                                                  3

            d)         Discuss the uses of sound.                                                                                                         2

                         m₁ = 39.2                    m₂ =15 kg

2.        

            Two bodies are placed 20 cm apart and they attack each other with force 9.81x10^-7N this

            attraction obeys a low.

            a)         Define gravitation.                                                                                                         1

            b)         Write down the laws of gravitation.                                                                                           3

            c)         Here we get a constant. What is its name? What is the value of that constant (mathematical) 3

            d)         From that law calculate the acceleration due to gravity.                                                  3

3.         A bob whose diameter is 0.58 cm in a fixed point by a thread of 99 cm long if a boy exerts a force and is left Gree. The bob start to oscillate.

            a)         Deduce the equation of simple pendulum.                                                                      2

            b)         Experimentally determine the value of acceleration due to gravity at a place using a

                        simple pendulum.                                                                                                                      4

            c)         The time required for two complete oscillation at that place is 4 S. Calculate time period.           2

            d)         Find the value of the acceleration due to gravity at that place.                                         4

4.         Mass of Mr. Karim is 15 kg. He hires a car of mass 35kg. he exerts a force of 100N for 2 sec.

As a result after 2 seconds. It gains a velocity.

            a)         Derive F = ma.                         4

            b)         What is the relation among displacement, acceleration and duration of motion?               4

            c)         What is the final velocity of Mr. Karim?                                                                         2

           

5.         A body of mass 3 kg moves east a with a velocity of 2 m/s. Another body of mass 1 kg moves westward with velocity of 2 m/s. At a certain time the bodies collide with each other and becomes a single body.

            a)         What is Newton's third law?                                                                                                     1

            b)         Deduce the law of conservation of momentum.                                                              5

            c)         What will be the velocity and direction of combined body?                                                        4