Practice Paper
Subject Physics (2019)
Class VIII Ch-FORCE AND PRESSURE
1.When the force applied on an object is doubled,how does the pressure exerted on the object change?
2.Define friction. Is it a contact force or non contact force?
3.Name the force acting between the two surfaces in contact and opposing the motion .
4.What is the resultant force of the two forces F1 and F2 acting on a body in the opposite direction ?
5.In the following situation identify the agent exerting the force and the object on which it acts.State the effect of force in each case.
(a) Squeezing a piece of lemon between the fingers to extract its juice.
(b) Taking out paste from a toothpaste tube.
(c) A load suspended from a spring while its other end is on a hook fixed to a wall.
(d) An athlete making a high jump to clear the bar at a certain height.
6.Name the forces acting on a plastic bucket containing water held above the ground level in your hand? Discuss why the forces acting on the bucket do not change in its state of motion.
7.An archer stretches her bow while taking aim at the target.She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms.
6.Name the forces acting on a plastic bucket containing water held above the ground level in your hand? Discuss why the forces acting on the bucket do not change in its state of motion.
7.An archer stretches her bow while taking aim at the target.She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms.
(a)To stretch the bow an archer applies a force that causes a change in its _______.
(b) The force applied by the archer to stretch the bow in an example of a ______ force.
(c)While the arrow moves towards its target,the force acting on it are due to ________ and of air.
8.When we press the bulb of a dropper with its nozzle kept in water, air in dropper seems to escape in the form of bubbles.Once we release the pressure on the bulb, water gets filled in the dropper. What is the cause of the rise of water in the dropper ?
9.How would 'thrust' on the bottom of a liquid level change if 'area' is doubled keeping the the 'pressure' same.
10.To which law, the statement "pressure applied to a liquid is transmitted equally in all direction" is applicable ?
11.What is the height of mercury column in a simple barometer at a sea level?
12.Define force and pressure.What are the S.I unit of force and pressure?
13.Why is difficult to cut vegetables with a blunt knife ?
14.Why are astronauts made to wear specially made suits to go into space?
15.What are the unbalanced forces?
16.Why is a sharp knife more effective is cutting a fruit than a blunt knife ?
17.Why is it comfortable to lift a school bag with broad straps than thin straps?
18.What is meant by the term atmospheric pressure ?
19.Describe with suitable examples the contact force and non contact force .
20.Tractor have large tires, bulldozers have caterpillar tracks and heavy buses trucks have eight rear wheel. Give one reason common to all these.
21.How does pressure due to a liquid held in a container vary with
8.When we press the bulb of a dropper with its nozzle kept in water, air in dropper seems to escape in the form of bubbles.Once we release the pressure on the bulb, water gets filled in the dropper. What is the cause of the rise of water in the dropper ?
9.How would 'thrust' on the bottom of a liquid level change if 'area' is doubled keeping the the 'pressure' same.
10.To which law, the statement "pressure applied to a liquid is transmitted equally in all direction" is applicable ?
11.What is the height of mercury column in a simple barometer at a sea level?
12.Define force and pressure.What are the S.I unit of force and pressure?
13.Why is difficult to cut vegetables with a blunt knife ?
14.Why are astronauts made to wear specially made suits to go into space?
15.What are the unbalanced forces?
16.Why is a sharp knife more effective is cutting a fruit than a blunt knife ?
17.Why is it comfortable to lift a school bag with broad straps than thin straps?
18.What is meant by the term atmospheric pressure ?
19.Describe with suitable examples the contact force and non contact force .
20.Tractor have large tires, bulldozers have caterpillar tracks and heavy buses trucks have eight rear wheel. Give one reason common to all these.
21.How does pressure due to a liquid held in a container vary with
(i)depth (ii)amount (iii)shape and size of the container .
22.How would pressure change if
22.How would pressure change if
(a) area is doubled keeping force constant.
(b) force is doubled keeping area constant.
23.State Pascal's law. Give a simple experiment to demonstrate this law.
24.Describe the simple barometer.
25.Define:
23.State Pascal's law. Give a simple experiment to demonstrate this law.
24.Describe the simple barometer.
25.Define:
(i)Contact and non contact forces
(ii)Balance and unbalanced force
(iii) Pressure and its unit
(iv)Pascal's law
(v)Simple barometer.
26.An object is pushed with a rod. The object starts moving. Is this force a contact or noncontact force ? Explain.
27.Why do all cutting instrument have sharp edges ? Give reason.
28.Can a rubber sucker be stuck on a rough surface? Give reason.
29.Why do heavy vehicles have broad tyres.
30.Write one word for the following:
26.An object is pushed with a rod. The object starts moving. Is this force a contact or noncontact force ? Explain.
27.Why do all cutting instrument have sharp edges ? Give reason.
28.Can a rubber sucker be stuck on a rough surface? Give reason.
29.Why do heavy vehicles have broad tyres.
30.Write one word for the following:
(a) The force acting between two electrically charged body .
(b) The single force which acts on a body to produce the same effect as is done by all the forces effectively.
(c)The force which produces an acceleration of 1m/s2 in an object of mass 1 kg.
(d) The pressure exerted by the air at any point on the earth. (e) Pressure applied to a liquid is transmitted equally in all directions.
(f) The force exerted by one object on another by virtue of their masses is .........
(g) A spring balance is used for measuring.......
(h) a given force is applied on a smaller area of contact, the pressure exerted by it.......
(i)The SI unit of pressure
(j) Pressure is defined as.
31.Write an expression for pressure.
32.Define resultant force.
33.When does a force come into play?
34.Define (i) muscular force (ii) frictional force (iii) magnetic force (iv) electrostatic force and (v) gravitational force.
35.A ball is rolled on the ground and it comes to rest after sometime even though no force is applied. Why?
36.Is it possible that a force changes the direction of motion but not the speed of an object?
37.Name the type of force:
31.Write an expression for pressure.
32.Define resultant force.
33.When does a force come into play?
34.Define (i) muscular force (ii) frictional force (iii) magnetic force (iv) electrostatic force and (v) gravitational force.
35.A ball is rolled on the ground and it comes to rest after sometime even though no force is applied. Why?
36.Is it possible that a force changes the direction of motion but not the speed of an object?
37.Name the type of force:
(a) Rain drops falling on the earth
(b) Holding a book on your hand
(c) Running a comb through your dry hair.
38.What is weight? What is the unit of weight?Name the device used for measuring the weight of an object.
39Define (i) 1 Newton (ii) 1 kgf (iii) 1gf
40.Name two contact forces and non contact forces .
41.A plastic comb when rubbed in dry hair can attract small pieces of paper. Name the force and its nature.
42.What is the relation between the newton and kilogram force.
43.What is the relation between 1 kilogram force and gram.
44.Two boys pull a rope from the two ends with a force equal to 100 N each. What is the resultant force.
45.The forces applied by the members of two team A and B in the game of tug of war are mentioned against each of them. Calculate the resultant force and name the winning team.
46.Differentiate between balanced and unbalanced forces.
47.Write the effects of force.with example.
48.Can a balanced force bring about any change in the state of motion of an object ?
49.What happened to the speed of moving object when it is pushed in the direction of its motion.
50.A body is act upon by two forces of 200 N and 300 N in the same direction.What is the resultant force acting on it.
51.If several forces act on a body in different direction,in which direction will the body move.
52.A girl weighing 50 kg is standing on pencil heels, each having an area of cross section of 1 cm2. An elephant weighing 2000 kg and foot area of cross section of 250 cm2 standing on the floor. Which of the two exerts force more pressure on the floor? Acceleration due to gravity equals to 10m/s2.
53.Give reason:
38.What is weight? What is the unit of weight?Name the device used for measuring the weight of an object.
39Define (i) 1 Newton (ii) 1 kgf (iii) 1gf
40.Name two contact forces and non contact forces .
41.A plastic comb when rubbed in dry hair can attract small pieces of paper. Name the force and its nature.
42.What is the relation between the newton and kilogram force.
43.What is the relation between 1 kilogram force and gram.
44.Two boys pull a rope from the two ends with a force equal to 100 N each. What is the resultant force.
45.The forces applied by the members of two team A and B in the game of tug of war are mentioned against each of them. Calculate the resultant force and name the winning team.
46.Differentiate between balanced and unbalanced forces.
47.Write the effects of force.with example.
48.Can a balanced force bring about any change in the state of motion of an object ?
49.What happened to the speed of moving object when it is pushed in the direction of its motion.
50.A body is act upon by two forces of 200 N and 300 N in the same direction.What is the resultant force acting on it.
51.If several forces act on a body in different direction,in which direction will the body move.
52.A girl weighing 50 kg is standing on pencil heels, each having an area of cross section of 1 cm2. An elephant weighing 2000 kg and foot area of cross section of 250 cm2 standing on the floor. Which of the two exerts force more pressure on the floor? Acceleration due to gravity equals to 10m/s2.
53.Give reason:
(a) The skiers he skiers use flat and long skies to slide on snow.
(b) The sledges are not provided with wheels
(c) The rear wheels of tractor are made broader
(d) The foundation of high rise building I kept wide
(e) Camel can walk through desert easily as compared to other animals
(f) Drawing pins, Alpins have relatively much larger top and highly pointed and sharpened lower end. (g) A dam is thicker at its base than at the top.
54.What are the factors on which pressure of fluid depends.
55.Name two parameters which define pressure.
56.Where is the pressure due to water higher in a dam near it's base or near its top?
57.How does pressure at a point within a liquid change with its depth?
58.On what principle, are the hydraulic disc brakes based?
59.Define atmospheric pressure ?
60.Write one difference between atmospheric pressure and liquid pressure .
61.How large is the atmospheric pressure ? Why we do not feel this force?
62.What is atmospheric pressure? Name the instrument that is used to measure atmospheric pressure at any place.Name the barometer that uses no liquid in it.
63.How does the atmospheric pressure change with altitude ?
64.What is the physiological effect of a sudden drop in pressure?
65.Mountaineers at high altitude sometimes experience bleeding through their nose. Why?
54.What are the factors on which pressure of fluid depends.
55.Name two parameters which define pressure.
56.Where is the pressure due to water higher in a dam near it's base or near its top?
57.How does pressure at a point within a liquid change with its depth?
58.On what principle, are the hydraulic disc brakes based?
59.Define atmospheric pressure ?
60.Write one difference between atmospheric pressure and liquid pressure .
61.How large is the atmospheric pressure ? Why we do not feel this force?
62.What is atmospheric pressure? Name the instrument that is used to measure atmospheric pressure at any place.Name the barometer that uses no liquid in it.
63.How does the atmospheric pressure change with altitude ?
64.What is the physiological effect of a sudden drop in pressure?
65.Mountaineers at high altitude sometimes experience bleeding through their nose. Why?
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