3.2 Understanding Pressure in Liquid

3.2Understanding Pressure in LiquidCHAPTER 3 FORCES AND PRESSURELearning OutcomesWhat is Pressure in Liquid?A liquid in a container exerts pressure because of its weight.Pressure in liquid acts in all directions.

Characteristics of Pressure in a liquid.

The pressure at any point in a liquid, at a particular depth, acts equally inThe pressure in a liquid acts equally in all direction and does not depend on the shape of the container.all directions.

The pressure in a liquid does __________ depend on the __________of its surface.

NOTarea

Experiments 3.1Variation of pressure with the depth of a liquidAim: to investigate the relationship between the pressure in a liquid with the depth of the liquid.Hypothesis:Variables: (a) Manipulated (b)Responding (c)FixedNote: The pressure at a depth, y of the liquid is represented by the distance spurts out from its point.

Procedure:1. Measure the depth of the each hole of the tank.2. Fill the water in the tank to make sure the pressure inside the tank is equal all the time.3. Observe what happen next.4.Measure the distance of the water spourts.

Tabulation data:Depth, h (cm)y (cm)Graph:Relate depth to pressure in a liquidThe pressure in a liquid is directly proportional to the depth.The pressure in a liquid increases with depth.

Pressure in liquid depends only on itsvertical distancefrom the surface of the liquid.

Pressure at A = Pressure at BRelate density to pressure in a liquidThe pressure in a liquid is directly proportional to the density of the liquid

Deriving the formula for Pressure in a liquid

AhDescribe applications of pressure in liquidsThe wall of a dam is much thicker at the bottom than at the top Because?

The water at the bottom of the damn is at a higher pressure than at the top.

Describe applications of pressure in liquids

A water tank is placed at higher level so that the water will have sufficient pressure to flow to consumers.Every home has a water tank above the roof for storage and provided a constant water pressure Describe applications of pressure in liquidsSubmarine is built with thick wall so as to withstand enormous pressure at grater depth.

The liquid solution is at a high pressure so it has sufficient pressure to flow into the veins of the patient.Describe applications of pressure in liquidsFigure (a) shows a container of herbal tea. Explain why the tea flows out of the tap at a fast speed.

The depth of water is high, so the water pressure is high. The atmospheric pressure in the container also push the water.Explain why when there is very little tea left in the container, it is easier for the tea to flow out of the tap when the container is tilted as shown in figure (b).

The depth of water is higher if it is tilted, so the water pressure is higher. So the water is easy to flow out.Why does the water pressure from a tap at the top floor is lower than the water pressure from a tap at the bottom floor of an apartment?

The tap at the top floor is at a higher level, so the depth is deeper and the water pressure is higher.Solve problems involving pressure in liquid

In the diagram on the right:How does the pressure at A compare with the pressure at B?How does the pressure at B compare with the pressure at D?How does the pressure at A compare with the pressure at C?

Pressure at B is higherEqualEqualCalculate the pressure at B due to the water.

P = 1000 x 10 x 2 = 20 000 PaIf the water in the system were replaced with paraffin, how would this affect the pressure at B?Decrease because paraffin is less densethan water.

P = 1000 x 10 x 0.4 = 4 000 PaP = 4 000 + (2500 x 10 x 0.7) = 21 500 PaCalculate the pressure at X level.

P = 1000 x 10 x (4 + 10) = 140 000 PaConclusionCharacteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the container

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.Pressure increases with depth

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.Pressure increases with depthPressure depends on the vertical depth, but not the length of liquid column.

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.Pressure increases with depthPressure depends on the vertical depth, but not the length of liquid column.All points at the same level in a liquid are at the same pressure

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.Pressure increases with depthPressure depends on the vertical depth, but not the length of liquid column.All points at the same level in a liquid are at the same pressurePressure does not depend on the surface area of the object.

Characteristics of Liquid PressurePressure in liquid does not depends onthe shape of the container.the size of the containerthe area of its surface.Pressure increases with depthPressure depends on the vertical depth, but not the length of liquid column.All points at the same level in a liquid are at the same pressurePressure does not depend on the surface area of the object.Pressure acts in all direction