Question

Aunt Matilda goes to a well and throws a penny straight down the well at 3.0 m/s. She hears a splash after 0.5 seconds. How deep is the well? a) 0.31 m b ) 0.91 m c) 1.54 m d) 2.73 m e) 5.30 m

Answer 1

Answer : The correct option is (d) 2.73 m

Explanation :

By the 2nd equation of motion,

$s=ut+\frac{1}{2}at^2$

where,

s = distance or height = ?

u = initial velocity  = 3.0 m/s

t = time = 0.5 s

a = acceleration due to gravity = $9.8m/s^2$

Now put all the given values in the above equation, we get:

$s=(3.0m/s)\times (0.5s)+\frac{1}{2}\times (9.8m/s^2)\times (0.5s)^2$

$s=2.73m$

Therefore, the correct option is (d) 2.73 m