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→Example Calculations
===Example Calculations===
{| class="wikitable"
| style="height:20px; width:300px; text-align:center;" |A fishing boat uses [[sonar]] to detect schools of fish beneath the boat. A sonar pulse is emitted and then received 0.042 [[second]]s later. The [[speed]] of [[sound]] in [[water]] is 1500m/s. Calculate how far beneath the boat the school of fish is located, correct to two [[Significant Figures|significant figures]].
| style="height:20px; width:300px; text-align:center;" |A [[bat]] uses [[sonar]] to locate its [[prey]]. The [[bat]] emits an [[ultrasound]] squeak which it hears [[reflect]]ed off its [[prey]] 30ms later. The [[speed]] of [[sound]] in [[air]] is 340m/s. Calculate the distance to the [[bat]]s [[prey]], correct to two [[Significant Figures|significant figures]].
|-
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities'''
v = 1500m/s
t = 0.042
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities'''
v = 340m/s
t = 30ms = 30x10<sup>-3</sup>s
|-
| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>x = v \frac{t}{2}</math>
<math>x = 1500 \frac{0.042}{2}</math>
<math>x = 31.5m</math>
<math>x \approx 32m</math>
| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>x = v \frac{t}{2}</math>
<math>x = 340 \frac{30 \times 10^{-3}}{2}</math>
<math>x = 5.1m</math>
|}