Measurement & Uncertainties

Question 1

If your stopwatch has a scale with 2 decimal places, what is the uncertainty in your time measurements?

Answer 1

±0.01s

Question 2

Absolute uncertainty

Answer 2

Difference between Actual value and correct value

Question 3

Percentage uncertainty

Answer 3

Absolute uncertainty ➗ correct value X 100

Question 4

approx diameter of atoms

Answer 4

10⁻¹⁰m

Question 5

atmospheric pressure

Answer 5

101.3kPa

Question 6

why will a cube submerged in liquid experience a buoyant force to counteract its weight?

Answer 6

the bottom surface is deeper than the top so experiences a greater force, resulting in a resultant upward force

Question 7

if 2 identical balls are dropped from a tall building, one a few seconds after the other, the distance between the balls will first increase, then stay constant - why?

Answer 7

the 1st ball is already at terminal velocity when the 2nd is dropped, so the gap gets smaller as the 2nd speeds up to reach terminal velocity - when it does, the gap becomes constant because the balls have the same terminal velocity

Question 8

necessary conditions to be able to use equations like v = s/t

Answer 8

no air resistance/surface is frictionless