Question 1 Report
A boy standing a distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound is 340ms1, how far is he from the cliff?
When sound travels to a reflecting surface and then back to the listener, it creates an echo. The distance from the listener to the reflecting surface can be calculated by dividing the total distance traveled by the sound by 2, because sound travels at a constant speed in all directions. Let's assume that the distance from the boy to the cliff is x meters. The sound will travel a distance of 2x meters: x meters from the boy to the cliff, and then x meters from the cliff back to the boy. The time taken for the sound to travel this distance is 0.5 seconds. We can use the formula speed = distance/time to find the speed of sound. Plugging in the values we get: 340 = 2x/0.5 Solving for x, we get: x = (340 x 0.5)/2 = 85 meters Therefore, the boy is standing 85 meters away from the cliff. The answer is option C.