Page 86 - Genius Kidz Prudence Learning Sc-8

! Any influence that can cause motion or move an object is called force.
! Total force acting on the object is equal to the resultant force.
! Force can change the direction, size and shape of the moving object.

! Force can be a contact or non-contact force.
! Force per unit area exerted vertically on the surface of the object is called pressure.
! Pressure is exerted by solids and fluids.

EXERCISE
EXERCISE

1. Multiple choice questions.
(a) Force is measured in:

(i) newton (ii) joules (iii) pascal (iv) kelvin
(b) Magnetic force is an example of :
(i) Contact force (ii) Non-contact force

(iii) Muscular force (iv) Frictional force
(c) Ball stops by itself on the ground after travelling a little distance because of:
(i) Friction (ii) Motion (iii) Sliding force (iv) Rolling friction

(d) Pressure applied by solids is inversely proportional to the ______________ that is acted upon.
(i) Volume (ii) Density (iii) Area (iv) None of these
(e) The relation between the S.I. unit of force and the weight of 1 kg mass is :

(i) 1 kg f = 1 N (ii) 1 Kg f = N (iii) 1 kg f = 9.8 N (iv) 1 N = 9.8 kg f

2. Fill in the blanks.
(a) Force is associated with ______________ and ______________ of the object.

(b) Force is an example of ______________ force.
(c) Like charges ______________ .
(d) Fruit always falls down towards earth due to ______________ .

(e) Pressure is the ______________ .

3. Match the columns.

Column A Column B
(a) Pressure (i) F = F + F + F
1 2 3
(b) Resultant force (ii) F = Zero

(c) F = F in opposite direction (iii) in all directions
1 2
(d) Liquids exert pressure (iv) Measurement of liquid pressure

(e) Manometer (v) Pascal

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