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GURUKUL CENTRAL ACADMY, CH.- 11- force & pressure, WORKSHEET-1, A. 1. c 2. d3. b 4. a5. f 6. e, B. 1. Stop an object in motion, 2. Change direction of an object in motion, 3. To reduce the speed of an object in motion, 4. Increase speed of an object in motion, 5. To set a stationary object in motion, C. 1. fluids, 2. gravitational pull 3. more, 4. manometer 5. Newton, WORKSHEET-2, Refer text book, , TEXTBOOK EXERCISES, Page 122 Try These, 1. Non-contact force, 2. Magnetic force 3. Newton, 4. Electric field 5. Resultant force, Page 127 Try These, 1. Pressure, 2. Blaise Pascal, 3. Manometer 4., pressure, , EXERCISES, A . 1. d. 2. d. 3. d. 4. b. 5. c. 6. c. 7. b. 8. c. 9. c. 10. c.

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GURUKUL CENTRAL ACADMY, B. 1. opposite, 2. muscular 3. Non-contact, 4. Gravitational, 5. weight 6. directly, indirectly, 7. greater 8. increases 9. decreases, C. 1. F 2. F3. F, , 4. F 5. F6. T 7. T, , D. 1. – c. 2. – d. 3. – e. 4. – b. 5. – a., E. 1. A push or a pull applied on an object to change its state, of rest or motion, its speed or direction, or its shape is, called force. The SI unit of force is newton., 2. Magnetic force, 3. Electrostatic force, 4. Speed increases, 5. Friction, 6. Blaise Pascal, 7. Manometer, 8. To separate iron scraps from the garbage dump and to, remove iron dust or small pieces from eyes in case of an, accident., 9. 9. Zero, F. 1. BY pushing or pulling., 2., , 3., , Contact forces including muscular force and frictional, force and non-contact forces including magnetic force,, electrostatic force and gravitational force., Contact Forces:

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GURUKUL CENTRAL ACADMY, Forces that arise when the objects are in direct or indirect, physical contact with each other are called the contact, forces., 2. Example muscular and frictional forces., Non-contact Forces:, 1. The force which can act even without any actual contact, between the two objects is called a non-contact force., 2. Example magnetic, electrostatic and gravitational forces., 1., , 4., , 5., , 6., , 7., , 8., , It will move faster., As with magnetic force, the electrostatic force can be felt, only when two charged objects are kept sufficiently close to, each other., Force applied on a surface per unit area is called pressure., Pressure depends upon the area over which the force is, applied as well as the magnitude of the force., • Needles and pins have sharp, pointed ends so that a small, force is enough to pierce a cloth or paper as the pressure, exerted will be more., • School bag and laptop bags have broad straps so that, weights of the objects in them exert lesser pressure on the, shoulders.

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GURUKUL CENTRAL ACADMY, G., , 1. 0 2. 5000 N/m 3. 30,000 N/m, 4. 200 N/m, 12.5 N/m, 5. 2000 N/m, 6. Net force = 0, state of cart = rest position, , H. 1. To reduce the area of contact so that less force is needed, to cut objects with them., 2., , 3., , 4., , 5., , 6., , At a depth, pressure due to water is about 100 times greater, than the atmospheric pressure., To increase friction between soles of the shoes and the, ground., Skis have a large area to reduce the pressure on the snow., This increases the area of contact between the load and the, head. The pressure on their head is thus reduced and they, find it easier to carry the load., Because the pressure of atmosphere acts on it.