Download Handout Topic 1 Uncertainty Practice 2 2015

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Topic 1 : Uncertainty Practice 2 Handout
1. Given the mass of the ball is 3.2 + 0.05g and the centripetal force ( F) acting
on the ball is 72.2 N + 0.1 N and its radius is 1.00 + 0.01m
a) Find the relative uncertainty for mass, force and radius.
b) Given the formula for centripetal force for circular motion is : F = mv2
r
Calculate velocity :
c) Find the relative uncertainty for the velocity:
d) Find the absolute uncertainty for the velocity
e) State your final answer
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2. The power ( P) dissipated in a resistor of resistance ( R ) in which there is a
current ( I ) is given by :
P = I2 R
The uncertainty in the value of the power is 16% and the uncertainty in the
value of the resistance of the resistor is 10% . Calculate the uncertainty of the
current running through the resistor.
3. The volume V of a cylinder of height h and radius r is given by the expression
V = π r2 h
In a particular experiment , r is to be determined from the measurements V and
h. The uncertainties in V and h are given below:
V
= + 10%
h = +4%
The approximate uncertainty in r is what ?
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