Question

A 200g ball begins falling from a height of 15m. If the (a) acceleration due to gravity is 10 m/s^2. How long do you calculate it will be before the object reaches the ground? Which formula will you use?

Answer 1

Answer:

1.732 seconds

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

Explanation:

s = Displacement of ball = 15 m

g = a = Acceleration due to gravity = $10\ \text{m/s}^2$

u = Initial velocity of the ball = 0

t = Time taken

From the kinematic equations we use the following formula

$s=ut+\dfrac{1}{2}at^2\\\Rightarrow 15=0t+\dfrac{1}{2}\times 10t^2\\\Rightarrow t=\sqrt{\dfrac{15\times 2}{10}}\\\Rightarrow t=\sqrt{3}=1.732\ \text{s}$

The object will reach the ground after 1.732 seconds.

The formula used is $s=ut+\dfrac{1}{2}at^2$.