Chap 6: Pressure

Question 1

What is pressure?

Answer 1

force acting per unit area

Question 2

Formula for pressure?

Answer 2

P = F/A
F = force (N), A = area (m^2)

Question 3

Unit of pressure?

Answer 3

SI: N/m^2
or pascal (Pa)

Question 4

Define density

Answer 4

mass per unit volume

Question 5

Formula for density

Answer 5

p (rho) = m/v
m = mass (kg), v = volume (m^3)

Question 6

Unit of density

Answer 6

SI: kg/m^3
or g/cm^3

Question 7

How to calculate density of liquids?

Answer 7

find mass / volume

Question 8

How to calculate density of solids?

Answer 8

water displacement method to find volume, divide accordingly

Question 9

Affect of gravitational field strength on density:

Answer 9

None. Density not affected by gravitational field strength

Question 10

How to calculate pressure of liquids?

Answer 10

height x density x gravitational field strength

P = hp(rho)g

Question 11

State Pascal’s Law

Answer 11

pressured is transferred equally to other parts of liquid when enclosed

Question 12

Formula for hydraulic press

Answer 12

P(1) = P(2)

F(x)/A(x) = F(y)/A(y)

*work done is the same
F(x)d(x) = F(y)d(y)`

Question 13

How to calculate total pressure?

Answer 13

pressure in liquid + pressure in atmosphere

Question 14

What is the atmospheric pressure at sea level?

Answer 14

1.013 x 10^5 Pa [760mm Hg]

Question 15

How does height affect atmospheric pressure?

Answer 15

If height increases, atmospheric pressure decreases

Question 16

How does depth affect pressure?

Answer 16

As depth increases, pressure increases

Question 17

What does a barometer do?

Answer 17

measure atmospheric pressure

[atmospheric pressure is height of mercury column of barometer]

Question 18

What does a manometer do?

Answer 18

measures pressure difference (for liquids & gases)

height difference of liquid is the gas pressure and atmospheric pressure difference