DELHI PUBLIC SCHOOL VADODARA

Academic Session 2024-2025

Revision Practice Paper - 1

Subject: Physics
Topic: Motion, Force and laws of motion, Gravitation, Work and Energy, Sound. Class: IX

Section A
1. The type of motion observed when an object moves in a circular path at a constant speed is
a) accelerated motion
b) uniform motion
c) non-uniform motion
d) retarded motion.
2. The inertia of an object causes the object to
a) decrease its speed.
b) increase its speed.
c) resist any changes in the state of its rest or motion.
d) decelerate due to friction.

3.1. The gravitational force of an object kept on the surface of earth is

a) equal to the mass of the object.
b) equal to the weight of the object on earth’s surface.
c) equal to the acceleration due to gravity.
d) equal to universal gravitational constant.
4. A car and a truck have same momentum then the kinetic energy of the car is
a) same as the kinetic energy of the truck.
b) greater than the kinetic energy of the truck.
c) smaller than the kinetic energy of the truck.
d) negligible as compare to the kinetic energy of the truck.
5. The low frequency sound produced when a simple pendulum vibrates is
a) audible sound.
b) ultrasound.
c) infrasound.
d) reflected sound.

6. Assertion(A): work done on a body to lift above the ground against gravity is always positive.
Reason(R): work done only depends on displacement of the body.
a) Both A and R are true and R is correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
7. Assertion (A): The position-time graph of a uniformly moving body have negative slope.
Reason(R): When the speed of a body decreases with time, the slope of the position- time graph is
negative.
a) Both A and R are true and R is correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
8. Assertion (A): Weight of a truck exerts less pressure on road as compared to its weight.
Reason (R): Truck has more than four wheels to decrease the pressure.
a) Both A and R are true and R is correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
9. Assertion: The work done is negative, if the force acting on a body causes retardation of its motion.
Reason: Work done depends on the angle between force and displacement.
a) Both A and R are true and R is correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true
10. Assertion: Two persons on the surface of Moon cannot talk to each other.
Reason: Sound cannot travel through vacuum.
a) Both A and R are true and R is correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true
Section B
11. The speed - time graph of a car is given below. From the graph calculate the total distance covered
by the car.

12. Luggage kept on the roof of a car is tied with a rope. Justify.
13. Gravitational force on a planet is 6 times than the gravitational force on earth. Calculate
a) acceleration due to gravity on the planet.
b) weight of an object of mass 50 kg on the planet.
14. Calculate the work done by a boy of mass 50 kg to increase his running speed from 9 km/h to
18 km/h.
15. Waves of frequency 100Hz are produced in a string as shown in the figure given below.

Find its
(i) amplitude.
(ii) wavelength.
(iii) velocity.
 Section C
16. A car starts from rest and accelerates 2.5 m/s2 to a distance of 150 m. Then it slows down with a
retardation of 1.5 m/s2 until the velocity becomes 10 m/s. Determine the total displacement of the
car.
17. The speed- time graph of a car is given below. Mass of the car is 1000kg. Calculate
a) the force applied at the beginning to accelerate the car from 0 m/s to 15 m/s.
b) the force applied at the end after 5 s to bring the car to rest.

18. State whether the velocity of a stone thrown vertically upwards decreases or increases. Justify your
answer.
19. Observe the given figure below and answer the following question.

a) At which position will the skier have maximum potential energy? Justify your answer.
b) Is the law of conservation of energy violated by the skier while moving from the point A to C?
Explain.
20. Name and explain the factors on which speed of sound depends.
Section D
21. a) Give reason for the following situations.
(i) Roads on the mountain are inclined inwards at turns.
(ii) Safety belts in vehicles help to protect passengers from injuries in the case of an accident.
(iii) In an athletic race, the athletes start the race with their foot resting on a solid
supporter.
b) What is the relation between Newton’s first law and second law of motion?
22. a) A stone is thrown vertically upward with an initial velocity of40 m/s. Given g = 10 m/s2.
Calculate:
(i) the maximum height reached by the stone.
(ii) the total displacement and distance covered by the stone.
b) A cube of edge 5 cm made of iron is completely immersed in ethanol of density 0.8 g/cm3. Mass
of the cube is 500 g. Given g = 10 m/s2.
(i) Will the cube float or sink. Justify your answer.
(ii) Calculate the buoyant force acting on it.
Section E
Read the following passages and answer the questions given below.

23. There is a difference in the way we use the term ‘work’ in day-to-day life and the way we use it in
science. For example, Kamali is preparing for examinations. She spends lot of time in studies. She
reads books, draws diagrams, organises her thoughts, collects question papers, attend classes,
discusses problems with her friends, and performs experiments. She expends a lot of energy on these
activities. In common parlance, she is ‘working hard’. All this ‘hard work’ may involve zero ‘work’
 if we go by the scientific definition of work.

a) Define power.
b) A girl pulled a trolley which is placed on a rough surface and it moves towards the girl.
(i) Name the different forces acting on the trolley.
(ii) Write the nature of the work done by each force.
c) A girl weighing 600 N climbs up a rope to a height of 10 m. She took 20 s to reach that height.
Calculate the power of the girl.
d) The freely falling body obeys the law of conservation of energy. Justify.
24. Like light, sound gets reflected at the surface of a solid or liquid and follows the same laws of
reflection. The directions in which the sound is incident and is reflected make equal angles with the
normal to the reflecting surface at the point of incidence, and the three are in the same plane. An
obstacle of large size which may be polished or rough is needed for the reflection of sound waves.
a) Define reverberation.
b) Draw two sound waves having equal amplitude but different frequencies.
c) The velocity of sound in air is 340 m/s. Calculate
(i) wavelength of the sound wave having frequency 256 Hz.
(ii) frequency of the sound wave having wavelength 0.85 m.
d) A man fired a bullet in front of the cliff and hears its echo after 3 s. Velocity of sound in air is
342 m/s. Calculate
(i) the distance of the man from the cliff.
(ii) the distance covered by the sound wave to hear an echo

-----End-----