REVISION QUESTIONS FOR CLASS 8

FORCE

   

• Fill in the blanks:

(1 marks each)

(1) To draw water from a well we have to ———  the rope.

(2)A charged body ———— an uncharged body towards it.

(3)To move a loaded trolley we have to ———— it.

(4)The north pole of a magnet ———— the north pole of another magnet.

(5)To stretch the bow, the archer applies a force that causes a change

in its ——.

(6)The force applied by the archer to stretch the bow is an example of ——— force.

(7)The type of force responsible for a change in the state of motion of the arrow is an example of a --------------------.

(8)While the arrow moves towards its target, the forces acting on it are due to ————

(9)At the same depth, a liquid exerts ———— pressure in all directions.

(10)Unlike poles of a magnet ———— each other.

VERY SHORT ANSWER QUESTIONS :

(1 marks )

1.A ball is in rest. Push it gently. Does the ball begin to move?

2.Name the term used to express the strength of a force.

3.What is force ?

4.When does net force becomes zero?

5.Give two examples of muscular force.

6.Give an example of non-contact force.

7.Give two examples of contact force.

8.What do you mean by electrostatic force?

SHORT ANSWER QUESTION

(2 marks )

1.A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?

2 .An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

3.A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.

ANSWER THESE QUESTIONS

(3 Marks)

     1.Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.

2.What are contact force. State different contact force.

3.What are non-contact force. State different non-contact force.

4.What are the various effects of force on different objects.

5.Explain force of gravity.

LONG ANSWER QUESTION

(5 marks each)

1.What is electrostatic force? Proof with the help of diagram.

2.What is friction? Explain with example types of non contact forces.

3.Prove that the force of friction depends on two surfaces in contact.

•MULTIPLE CHOICE QUESTION:

1.An example of contact force is:

(i)Gravitational force

(ii)Frictional force

(iii)Magnetic force

(iv)Electro-static force

2.An example of a non-contact force is:

(i)Magnetic force

(ii)Muscular force

(iii)Frictional force

(iv)all of these

3.If force is applied to an object in the direction of its motion. Its speed will:

(i)decreased

(ii)increases

(iii)remain unchanged

(iv)none of these

4.The SI unit if force is

(i)Newton

(ii)Newton/metre2

(iii)Pascal

(iv)none if these

5.Force of friction brings about a:

(i)change in speed of the object

(ii)change in shape of the object

(iii)change in direction of the object

(iv)none of these

6.Which force do you use when you ride a bicycle?

(i)Muscular force

(ii)Frictional force

(iii)Electrostatic force

(iv)Magnetic force