Pressure

Question 1

What is pressure?

Answer 1

Force/ area
(Force divided by area)

Question 2

What is force measure in?

Answer 2

Newtons (N)

Question 3

What is area measured in?

Answer 3

Metres squared
It can also be measured in cm squared or mm squared giving pressure in n/cm squared and n/mm squared

Question 4

Why can you lie down on a bed of nails without having any nail break your skin, but if you step on a single nail it will go right through your foot?

Answer 4

The weight is spread out over many nails so pressure is much less on bed of nails

Question 5

Give an example of high and low pressure and an explanation.

Answer 5

pin (high pressure)- small surface area so that the force applied results in a large pressure

snow shoes (low pressure)- spread persons’s weight over larger area so that pressure on the ground is small.

Question 6

To convert kg to n what do we do?

Answer 6

x10

Question 7

To convert g to n what do we do?

Answer 7

Change g into kg first and then x10

Question 8

A girl (mass of 50kg) is balancing on a single stiletto heel (area 1cm squared). What is her pressure on the floor? Show working.

Answer 8

50kg = 500N
P= 500N/1cm squared
= 500N/cm squared

Question 9

An elephant of mass 2 tonnes (2000kg) stands on one foot (area 1000cm squared)
What pressure does it exert? Show working.

Answer 9

P= force/area
P=20000N/1000cm squared
= 20N/cm squared