Question

A student measures T for one length l to determine the value of g. Time T  1.9 s ±0.1 s and length l 0.880m ±0.001m. Calculate the fractional uncertainty in g.

Answer 1

Explanation:

The student modifies the simple pendulum of length L so that, after release, it swings

for a quarter of a cycle before the string strikes a horizontal thin edge. For the next

half cycle, the pendulum swings with a shorter length x. The string then leaves the

horizontal thin edge to swing with its original length L.

before release after release

string

small mass

L

horizontal

thin edge

x

motion of pendulum

The length L of the string is kept constant during the experiment. The vertical position

of the horizontal thin edge is varied to change x.

Answer 2

Answer:

0.106

Explanation:

Re-arrange the equation giving : $\frac{l}{T^2} = g$ (ignoring the 2pi)

then calculate fractional uncertainty for g

$\frac{0.001}{0.88} + 2*\frac{0.1}{1.9} = 0.106$