Page 126 - Science Class 08

4. The unit of pressure is:
2
(a) Newton (N) (b) N/m
2
(c) m /N (d) Celcius
5. _____________ is the standard atmospheric pressure.
(a) 260 mm Hg (b) 760 mm Hg

(c) 1070 mm Hg (d) 50 mm Hg
B. Fill in the blanks.
1. The force generated by an engine is also an example of _______________ force.
2. Fric on is caused _______________ by the _______________ of two sliding objects.

3. The brakes of vehicle cannot work without _______________ .
4. The streamlined body of a water transport helps it in moving fast by _______________
fric on.
5. The bigger unit of pressure is _______________ .
C. Write True or False.

1. Force can move a sta onary object.
2. The sole of your shoes wear out in a few months due to fric on.
3. The tyres of motor vehicles have grooves that reduce the fric on.
4. Liquids exert pressure in only two direc ons.

5. Atmospheric pressure acts upon us all the me.
D. Match the following columns.
Column I Column II

1. Fric onal force a. Transfer of electron
2. Gravita onal force b. Engine
3. Electrosta c force c. Wearing out of sole
4. Magne c force d. Earth

5. Mechanical force e. Electric bell
E. Very short answer ques ons.
1. What is force?
2. What is contact force?

3. Name the three types of non-contact forces.
4. What is fric on?
5. Why do we lubricate machines?
6. Write any two disadvantages of fric on.

7. What is pressure?
8. Write any one applica on of pressure in our daily life.
9. What is atmospheric pressure?

10. Write any one effect of atmospheric pressure.

126 Science-8