PHYSICS X ICSE CHAPTERWISE SOLVED PAPERS 2022-2000
1. FORCE
1. The relation between CGS and SI unit of moment of force is 2021 (Semester-I)
(a) 1 N-m =105 dyne-cm
(b) 1 N-m =105 dyne
(c) 1 N-m =107 dyne-cm
(d) 1 dyne-cm =107 N-m
2. The diagram below shows the balanced position of a meter scale. 2021 (Semester-I)
Which one of the following diagrams shows the correct position of the scale, when it is supported at the centre?
3. What is the weight of a body placed at the centre of the earth? 2014
4. State the SI unit of the momentum of the body. 2002
5. (i) Define moment of force. 2020
6. (i) Define couple.
(ii) State the SI unit of moment of couple. 2019
7. A brass ball is hanging from a stiff cotton thread. Draw a neat labelled diagram showing the forces acting on
the brass ball and cotton thread. 2017/14
8. The distance between two bodies is doubled. How is the magnitude of gravitational force between them
affected? 2017
9. Why is a jack screw provided with a long arm? 2017
10. (i) Give an example of a non-contact force which is always of attractive nature.
(ii) How does the magnitude of this non-contact force on the two bodies depend on the distance of separation
between them? 2016
11. (i) Define equilibrium.
(ii) In a beam balance, when the beam is balanced in a horizontal position, it is in ______ equilibrium.
2015
12. When a body is placed on a table top, it exerts a force equal to its weight downwards on the table top but
does not move or fall.
,(i) Name the force exerted by the table top.
(ii) What is the direction of the force? 2015
13. (i) On what factor does the position of the centre of gravity of a body depend?
(ii) What is the SI unit of the moment of force? 2015
14. Name the factors affecting the turning effect of a body. 2015
15. A nut is opened by a wrench of length 20 cm. If the least force required is 2N, find the moment of force
needed to loosen the nut. 2015
16. A force is applied on
(i) a rigid body and (ii) a non-rigid body.
How does the effect of the force differ in the above two cases? 2014
17. (i) Where is the centre of gravity of a uniform ring situated?
(ii) The position of the centre of gravity of a body remains unchanged even when the body is
deformed. State whether the statement is true or false. 2013
18. One end of a spring is kept fixed while the other end is stretched by a force as shown in the
diagram.
(i) Copy the diagram and mark on it the direction of the restoring force.
(ii) Name one instrument which works on the above principle. 2013
19. Give any two effects of a force on a non-rigid body. 2013
20. A boy of mass 30 kg is sitting at a distance of 2 m from the middle of a see-saw. Where should a boy of
mass 40 kg sit, so as to balance the see-saw? 2012
21. (i) What is meant by the term moment of force?
(ii) If the moment of force is assigned a negative sign, then will the turning tendency of the force be clockwise
or anti-clockwise? 2012
22. (i) What are non-contact forces?
(ii) How does the distance of separation between two bodies affect the magnitude of the non-contact force
between them? 2012
23. (i) Define 1 kgf. (ii) How is it related to the SI unit of force? 2012
24. A man can open a nut by applying a force of 150 N by using a lever handle of length 0.4 m.
What should be the length of the handle, if he is able to open it by applying a force of 60 N? 2011
25. Where does the position of centre of gravity lie for
(i) a circular lamina? (ii) a triangular lamina? 2011
26. (i) Define one newton.
(ii) Write the relation between SI unit and CGS unit of force. 2011
27. A body of mass 1.5 kg is dropped from the 2nd floor of a building which is at a height of 12 m.
What is the force acting on it during its fall? (Take, g = 9.8 m/s2) 2008
28. A uniform meter scale is in equilibrium as shown in the figure given below.
,(i) Calculate the weight of the meter scale.
(ii) Which of the following option is correct to keep the ruler in equilibrium, when 40 gf-wt is
shifted to 0 cm mark? F is shifted towards 0 cm or F is shifted towards 100 cm. 2019
29. A half-meter rod is pivoted at the centre with two weights of 20 gf and 12 gf suspended at a
perpendicular distance of 6 cm and 10 cm from the pivot respectively, as shown below.
(i) Which of the two forces acting on the rigid rod causes clockwise moment?
(ii) Is the rod in equilibrium?
(iii) The direction of 20 kgf force is reversed. What is the magnitude of the resultant moment of the forces on
the rod? 2018
30. Two forces each of 5 N act vertically upwards and downwards, respectively. On the two ends of a uniform
meter rule which is placed at its mid-point as shown in the diagram. Determine the
magnitude of the resultant moment of these forces about the mid-point. 2014
SOLUTIONS
1. (c) We know that, -
1 newton =105 dyne
1 N-m = 105 × 102 dyne-cm
1 N-m = 107 dyne-cm
2. (a)
Let us suppose left side have mass m and right side have mass m'.
Consider centre of mass at 20 cm and at 70 cm for left and right side respectively.
By moment of force, mg × 20 = m'g × (30)
3
⇒ m = 2 m'
Here, left hand side is more heavy, so it will bend or rotate more towards left side as compared to
right side when fulcrum is placed at 50 cm mark.
Correct option is (a).
, 3. The weight of a body placed at the centre of the earth is zero, because the value of g at the centre of earth is
zero.
4. The SI unit of the momentum of the body kilogram metre per second (kg-ms-1).
5. The turning effect produced by a force on a rigid body about a point, pivot or fulcrum is called moment of a
force or torque. It is the product of the magnitude of the force and the perpendicular distance of the line of
action of force from the axis of rotation.
6. (i) A couple is a pair of forces equal in magnitude, oppositely directed and displaced by perpendicular
distance or moment. The simplest kind of couple consists of two equal and opposite forces whose lines of action
do not coincide. This is called a simple couple.
(ii) The moment of couple is defined as the product of either force and the perpendicular distance between the
line of action of forces.
7. Diagram showing the forces on the ball is given below
The forces acting on the brass ball are
(i) Weight (mg) of the brass ball is acting vertically downwards.
(ii) Tension (T) along the string.
8. Let m1 and m2 are the two bodies separated by a distance r. Gravitational force between them is
𝐺𝑚1𝑚2
F1 = 𝑟2
…(i)
where, G = gravitational constant.
If the distance between two bodies is doubled, then new gravitational force between them will be
𝐺𝑚1𝑚2
F= (2𝑟)2
𝐺𝑚1 𝑚2
= …(ii)
4𝑟2
Now, if we divide Eq. (i) by Eq. (ii), we get
𝐺𝑚1 𝑚2
𝐹 𝑟2
= 𝐺𝑚1 𝑚2
𝐹1
4𝑟2
𝐹
⇒ F1 = 4
1. FORCE
1. The relation between CGS and SI unit of moment of force is 2021 (Semester-I)
(a) 1 N-m =105 dyne-cm
(b) 1 N-m =105 dyne
(c) 1 N-m =107 dyne-cm
(d) 1 dyne-cm =107 N-m
2. The diagram below shows the balanced position of a meter scale. 2021 (Semester-I)
Which one of the following diagrams shows the correct position of the scale, when it is supported at the centre?
3. What is the weight of a body placed at the centre of the earth? 2014
4. State the SI unit of the momentum of the body. 2002
5. (i) Define moment of force. 2020
6. (i) Define couple.
(ii) State the SI unit of moment of couple. 2019
7. A brass ball is hanging from a stiff cotton thread. Draw a neat labelled diagram showing the forces acting on
the brass ball and cotton thread. 2017/14
8. The distance between two bodies is doubled. How is the magnitude of gravitational force between them
affected? 2017
9. Why is a jack screw provided with a long arm? 2017
10. (i) Give an example of a non-contact force which is always of attractive nature.
(ii) How does the magnitude of this non-contact force on the two bodies depend on the distance of separation
between them? 2016
11. (i) Define equilibrium.
(ii) In a beam balance, when the beam is balanced in a horizontal position, it is in ______ equilibrium.
2015
12. When a body is placed on a table top, it exerts a force equal to its weight downwards on the table top but
does not move or fall.
,(i) Name the force exerted by the table top.
(ii) What is the direction of the force? 2015
13. (i) On what factor does the position of the centre of gravity of a body depend?
(ii) What is the SI unit of the moment of force? 2015
14. Name the factors affecting the turning effect of a body. 2015
15. A nut is opened by a wrench of length 20 cm. If the least force required is 2N, find the moment of force
needed to loosen the nut. 2015
16. A force is applied on
(i) a rigid body and (ii) a non-rigid body.
How does the effect of the force differ in the above two cases? 2014
17. (i) Where is the centre of gravity of a uniform ring situated?
(ii) The position of the centre of gravity of a body remains unchanged even when the body is
deformed. State whether the statement is true or false. 2013
18. One end of a spring is kept fixed while the other end is stretched by a force as shown in the
diagram.
(i) Copy the diagram and mark on it the direction of the restoring force.
(ii) Name one instrument which works on the above principle. 2013
19. Give any two effects of a force on a non-rigid body. 2013
20. A boy of mass 30 kg is sitting at a distance of 2 m from the middle of a see-saw. Where should a boy of
mass 40 kg sit, so as to balance the see-saw? 2012
21. (i) What is meant by the term moment of force?
(ii) If the moment of force is assigned a negative sign, then will the turning tendency of the force be clockwise
or anti-clockwise? 2012
22. (i) What are non-contact forces?
(ii) How does the distance of separation between two bodies affect the magnitude of the non-contact force
between them? 2012
23. (i) Define 1 kgf. (ii) How is it related to the SI unit of force? 2012
24. A man can open a nut by applying a force of 150 N by using a lever handle of length 0.4 m.
What should be the length of the handle, if he is able to open it by applying a force of 60 N? 2011
25. Where does the position of centre of gravity lie for
(i) a circular lamina? (ii) a triangular lamina? 2011
26. (i) Define one newton.
(ii) Write the relation between SI unit and CGS unit of force. 2011
27. A body of mass 1.5 kg is dropped from the 2nd floor of a building which is at a height of 12 m.
What is the force acting on it during its fall? (Take, g = 9.8 m/s2) 2008
28. A uniform meter scale is in equilibrium as shown in the figure given below.
,(i) Calculate the weight of the meter scale.
(ii) Which of the following option is correct to keep the ruler in equilibrium, when 40 gf-wt is
shifted to 0 cm mark? F is shifted towards 0 cm or F is shifted towards 100 cm. 2019
29. A half-meter rod is pivoted at the centre with two weights of 20 gf and 12 gf suspended at a
perpendicular distance of 6 cm and 10 cm from the pivot respectively, as shown below.
(i) Which of the two forces acting on the rigid rod causes clockwise moment?
(ii) Is the rod in equilibrium?
(iii) The direction of 20 kgf force is reversed. What is the magnitude of the resultant moment of the forces on
the rod? 2018
30. Two forces each of 5 N act vertically upwards and downwards, respectively. On the two ends of a uniform
meter rule which is placed at its mid-point as shown in the diagram. Determine the
magnitude of the resultant moment of these forces about the mid-point. 2014
SOLUTIONS
1. (c) We know that, -
1 newton =105 dyne
1 N-m = 105 × 102 dyne-cm
1 N-m = 107 dyne-cm
2. (a)
Let us suppose left side have mass m and right side have mass m'.
Consider centre of mass at 20 cm and at 70 cm for left and right side respectively.
By moment of force, mg × 20 = m'g × (30)
3
⇒ m = 2 m'
Here, left hand side is more heavy, so it will bend or rotate more towards left side as compared to
right side when fulcrum is placed at 50 cm mark.
Correct option is (a).
, 3. The weight of a body placed at the centre of the earth is zero, because the value of g at the centre of earth is
zero.
4. The SI unit of the momentum of the body kilogram metre per second (kg-ms-1).
5. The turning effect produced by a force on a rigid body about a point, pivot or fulcrum is called moment of a
force or torque. It is the product of the magnitude of the force and the perpendicular distance of the line of
action of force from the axis of rotation.
6. (i) A couple is a pair of forces equal in magnitude, oppositely directed and displaced by perpendicular
distance or moment. The simplest kind of couple consists of two equal and opposite forces whose lines of action
do not coincide. This is called a simple couple.
(ii) The moment of couple is defined as the product of either force and the perpendicular distance between the
line of action of forces.
7. Diagram showing the forces on the ball is given below
The forces acting on the brass ball are
(i) Weight (mg) of the brass ball is acting vertically downwards.
(ii) Tension (T) along the string.
8. Let m1 and m2 are the two bodies separated by a distance r. Gravitational force between them is
𝐺𝑚1𝑚2
F1 = 𝑟2
…(i)
where, G = gravitational constant.
If the distance between two bodies is doubled, then new gravitational force between them will be
𝐺𝑚1𝑚2
F= (2𝑟)2
𝐺𝑚1 𝑚2
= …(ii)
4𝑟2
Now, if we divide Eq. (i) by Eq. (ii), we get
𝐺𝑚1 𝑚2
𝐹 𝑟2
= 𝐺𝑚1 𝑚2
𝐹1
4𝑟2
𝐹
⇒ F1 = 4
