WAEC - Physics (2004 - No. 33)
A girl stand 80m away from a tall cliff and blows a whistle. If the speed of sound in air is 330ms-1, how long would it take for her to hear the echo of the sound?
2.062s
0.970s
0.485s
0.242s
解释
t = \(\frac{2x}{v} = \frac{2 \times 80}{330} = 0.485s\)