find the speed of sound. If it is x m/s, then you have two equal distances.
The distance fallen is s = 5t^2, so the falling time is √(s/5)
The sound takes s/x seconds to come back.
√(s/5) + s/x = 3
So, look up x and do the math for s, the well depth.
The rest then come easily...
A falling stone accelerates at a constant rate of 10ms^2. It is dropped from rest down a deep well and 3s later a splash is heard as it hits the water below.(1) How fast will it be moving as it hits the water? (2)What will be its average speed over the three seconds ? (3) how deep is the well ?
6 answers
I don't. know
Dereje
Oct 27, 2015
Teacher
1) 30m/s
2) 15m/s
3) 45m
2) 15m/s
3) 45m