P11- Force and pressure

Question 1

Pressure def?
Units?

Answer 1

Force per unit area
Pascals (Pa)= 1N/m²

Question 2

Why does a sharp knife cut easier than a blunt one?

Answer 2

Has a smaller area of contact, pressure is bigger than a blunt knife with same force. Has a bigger cutting effect.

Question 3

What happens to the pressure of a liquid with an increased depth, why?
When will liquid stop flowing?

Answer 3

Pressure of liquid increases with depth, greater mass of water above, increased force acting down
When the pressure along the same horizontal level is constant

Question 4

What happens to the pressure of a liquid with an increased density?

Answer 4

Pressure increases as density increases

Question 5

What is atmospheric pressure?

Answer 5

Air particles colliding with surfaces and creating pressure on them

Question 6

High altitude affecting pressure and density?

Answer 6

Atmospheric pressure decreases, less air above than at a lower altitude
Density decreases

Question 7

What is upthrust in a liquid?

Answer 7

The upward force on an object due to the liquid

Question 8

Float or sink when..
(weight and upthrust)

Answer 8

Float when weight is equal to upthrust
Sink when weight is greater than upthrust

Question 9

What happens to the forces when an object reaches the bottom?

Answer 9

Upthrust and normal contact force balance to equal weight