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Worksheet 2 Friction  A. Fill in the Blanks Friction always acts in the __________ direction to motion. The force of friction is greater between __________ surfaces. The irregularities on surfaces cause __________. __________ are used to reduce friction in machines. A __________ balance measures the force of friction. B. Conceptual Questions Why does a rolling object experience less friction than a sliding object? Why are shoes designed with grooves or tread patterns on their soles? What is the role of spring balance in studying friction? C. Think & Apply  A wooden block is pulled on a rough table and then on a smooth table. Predict and explain the difference in friction. Why do ball bearings reduce friction in machines? If friction didn’t exist, what challenges would we face in daily life? Think of at least three situations. D. Advantages and Disadvantages  List two situations where friction is helpful and two where it is not useful. Suggest two ways to reduce unwant...

Pressure in Liquids and Gases Worksheet 1 A. Fill in the Blanks Pressure in liquids __________ with depth. Liquids and gases are also known as __________. Gases exert pressure in __________ directions. Pressure is measured using an instrument called __________. The unit of pressure in the SI system is __________. B. Reasoning-Based Questions Why do deep-sea divers wear specially designed suits? Why do we not feel the atmospheric pressure around us? Why do aeroplanes have pressurised cabins for passengers safety while flying high in the atmosphere? Why are dams constructed thicker at the bottom than at the top? C. Diagram-Based Question Draw a diagram to show how pressure increases with depth in a liquid. In the diagram of a closed container, mark how gas pressure is exerted on all walls.