Changes

| 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]].