Total time in between the dropping of the stone and hearing of the echo = 8.9 s
Time taken by the sound to reach the person = 0.9 s
Time taken by the stone to reach the bottom of the well = 8.9 - 0.9 = 8 seconds
Initial speed (u) = 0 m/s
Acceleration due to gravity (g) = 9.8 m/s^2
Time taken (t) = 8 seconds
Let the depth of the well be h.
Using the second equation of motion:

h = 313.6 m
Hence, the depth of the well is 313.6 m
F = ma
F = 85×(5-3)÷3
F = 85×(2÷3)
F = 85×0.667
F = 56.67N
Answer:

Explanation:
As we know that the equation of SHM is given as

here we know that

here we have

now we have


now we have

now at t = 2.3 s we have


Answer:

Explanation:
Given that

We know that acceleration a given as




We know that



So the magnitude of force F
