Question

3. The time for a swing to move forward and backward can be determined by the formula

T = 2√√√15₁
T represents the time, in seconds, taken by the swing to move through one
complete cycle (forward and back) and L represents the length of the rope supporting the swing.
9.8
Determine the length of the rope supporting a swing that takes 3.4 seconds to move through one
complete cycle. Show all steps and round the answer to the nearest tenth of a metre.

Answer 1

Explanation:

T = 2×pi × sqrt(L/9.8)

now we know the time the swing should take for a complete back and forth cycle : 3 4 seconds.

the only unknown variable is now L (the length of the rope) :

3.4 = 2×pi × sqrt(L/9.8)

3.4/(2pi) = sqrt(L/9.8)

(3.4/(2pi))² = L/9.8

3.4²/(4pi²) = L/9.8

11.56/(4pi²) = L/9.8

2.89/pi² = L/9.8

9.8 × 2.89/pi² = L = 2.869618563... m ≈ 2.9 m