Force Past Paper PDF

Class X Chapter 1 – Force Physics ______________________________________________________________________________ EXERCISE- 1 (A) Question 1: What are contact forces? Give two Examples. Solution 1: The forces which act on bodies when they are in physica...

Class X Chapter 1 – Force Physics ______________________________________________________________________________ EXERCISE- 1 (A) Question 1: What are contact forces? Give two Examples. Solution 1: The forces which act on bodies when they are in physical contact, are called contact forces. For e.g. frictional force and force exerted on two bodies during collision. Question 2: What are non – contact forces? Give two example. Solution 2: The forces experienced by bodies even without being physically touched, are called the non- contact forces. For e.g. Gravitational force and Electrostatic force. Question 3: Classify the following amongst contact and non-contact forces. (a) Frictional force (b) normal reaction force, (c) force of tension in a string (d) gravitation force (e) electrostatic force (f) magnetic force Solution 3: Contact force: (a) frictional force (b) normal reaction force (c) force of tension in a string Non-contact force: (d) gravitational force (e) electric force (f) magnetic force Question 4: Give one example in each case where: (a) the force is of contact and (b) Force is at a distance. Solution 4: (a) Force exerted on two bodies during collision. (b) Magnetic force between magnetic poles. ____________________________________________________________________________________ Class X Chapter 1 – Force Physics ______________________________________________________________________________ Question 5: (a) A ball is hanging by a thread from the ceiling of the roof. Draw a neat labelled diagram showing the forces acting on the ball and the string. (b) A spring is compressed against a rigid wall. Draw a neat and labelled diagram showing the forces acting on the spring. Solution 5: Question 6: State one factor on which the magnitude of a non – contact force depends. How does it depend on the factor stated by you? Solution 6: The magnitude of a non-contact force depends on distance of separation of two bodies. Magnitude of force decreases as the distance increases. ____________________________________________________________________________________ Class X Chapter 1 – Force Physics ______________________________________________________________________________ Question 7: The separation between two masses is reduced to half. How is the magnitude of gravitational force between them affected? Solution 7: The magnitude of gravitational force between two masses will become four times as gravitational force varies inversely as the square of distance of separation. Question 8: Define the term ‘force’? Solution 8: A Force is that physical cause which changes(or tends or change) either the size or shape or the state of rest or motion of the body. Question 9: State the effects of a force applied on (i) a non- rigid, and (ii) a rigid body. How does the effect of the force differ in the two cases? Solution 9: A force when applied on a non-rigid body changes the inter-spacing between its constituent particles and therefore causes a change in its dimensions and can also produce motion in it. On the other hand, a force when applied on a rigid body, does not change the inter-spacing between its constituent particles and therefore it does not change the dimensions of the body but causes motion in it. Question 10: Give one example in each of the following cases: (a) A force stops a moving body (b) A force moves a stationary body (c) A force changes the size of a body (d) A force changes the shape of a body Solution 10: (a) A fielder on the ground stops a moving ball by applying a force with his hands. (b) The pull exerted by horse makes a cart moves. (c) In a cycle pump, when the piston is lowered, the air is compressed to occupy a less volume. (d) On pressing a piece of rubber, its shape changes. ____________________________________________________________________________________ Class X Chapter 1 – Force Physics ______________________________________________________________________________ Question 11: State Newton’s first law of motion. Why is it called the law of inertia? Solution 11: Newton's first law of motion: A body continues to be in its state of rest or of uniform motion in a straight line unless an external force is applied on it. It is called the law of inertia because it tells that every material body has a property by virtue of which it resists the change in its state of rest or in its state of motion. This property is called inertia. Question 12: Define the term linear momentum. State its S.I. unit. Solution 12: The product of mass and velocity of the body is called linear momentum. S.I. unit of linear momentum is kg m s-1. Question 13: (a) Write an expression for the change in momentum of a body of mass m moving with velocity v if (i) v ≪ c and (ii) v ⟶ c. (b) State the condition when the change in the momentum of a body depends only on the change in its velocity. Solution 13: (i) When v