P11 (Force And Pressure)

Question 1

4 Stages of investigating springs exsperiment

Answer 1

1) Measure the natural length of the spring, using a clamped stand with a millimetre ruler at eye level
2) Add a mass to the spring and allow it to rest. Record the new length and the extension is the change in length
3) repeat with different masses
4) plot a force-extension graph

Question 2

Straight line in force-extension graph

Answer 2

• force and extension are directly proportional

- gradient = spring constant

Question 3

Curve in the force-extension graph

Answer 3

• non linear relationship as it stretches more for each unit of force
• exceeding limit of proportionality

Question 4

Elastic potential energy (J) =

Answer 4

0.5 x Spring Constant(N/M) x extension^2 (M)

Question 5

Pressure

Answer 5

• force applied in a given area

- exert force as the collide with other surfaces

Question 6

2 things pressure in liquids depend on

Answer 6

• density as more particles in a certain space which means an increase in collisions
• depth as there are more particles and the weight increases

Question 7

2 pressure (Pa) formulas

Answer 7

= Force (N) / Area (M^2)

= Height(M) x Gravitational FS (N/Kg) x density (Kg/M^3)

Question 8

Upthrust

Answer 8

• pressure exerted on object submerged
• increase depth means increased force and is more than the force from the top
• creates a resultant force

Question 9

Floating

Answer 9

• when the upthrust is equal to the objects weight

- object less dense displaces equal fluid to the weight

Question 10

Sinking

Answer 10

• higher density
• fluid unable to displace the weight of the object
• weight higher than the upthrust

Question 11

How submarines work

Answer 11

• to sink fill water tanks so weight is more than upthrust

- to rise fill tanks with compressed air so more upthrust

Question 12

Effect of height on atmospheric pressure

Answer 12

higher altitudes atmosphere is less dense as fewer molecules are colliding with the surface