P15 | forces & matter

Question 1

why do water particles in a beaker exert a force on the beaker?

Answer 1

• the particles have mass therefore when they collide with a surface they exert a force
• this force causes pressure at right angles to that surface

Question 2

where is pressure the highest in Earth’s atmosphere?

Answer 2

at the bottom due to the mass of the particles above

Question 3

where is the pressure highest in the ocean?

Answer 3

at the bottom due to the mass of the water particles above

Question 4

why does atmospheric pressure decrease as you go higher in the atmosphere?

Answer 4

• as altitude increases, the atmosphere pressure decreases in a non-linear fashion
• this is because as the altitude increases, the atmosphere becomes less dense
• this means that the space between air molecules increases leading to less particle collisions
• which means less pressure

Question 5

why does water pressure increase as you go deeper in the ocean?

Answer 5

• as deepness increases, the water pressure increases in a linear fashion
• this is because as depth increases, the weight of the water above increases
• this means that the number of particles above/the mass is increasing which leads to more particle collisions
• which means more pressure

Question 6

pressure in a liquid formula

Answer 6

pressure = height x density x gravitational field strength