Question

A 100g object begins falling from a height of 5 meters. If g, the acceleration of gravity, is 10 m/s2, how long do you calculate it will be before the object reaches the ground? (Recall the formula for distance with constant acceleration from zero speed is ½at2.) 0.5 s 1.0 s 5.0 s 10 s 50 s

Answer 1

Answer:

The correct option is b: 1.0 s.

Explanation:

To find the time (t) at which the object reaches the ground we need to use the next equation:

$y_{f} = y_{0} + v_{0}t - \frac{1}{2}gt^{2}$   (1)

Where:

$y_{f}$: is the final height = 0                    

$y_{0}$: is the initial height = 5 m

$v_{0}$: is the initial speed = 0 (it falls from rest)

g: is the gravity = 10 m/s²

By entering the above values into equation (1) we have:

$0 = 5m - \frac{1}{2}10 m/s^{2}t^{2}$

$t = \sqrt{\frac{2*5 m}{10 m/s^{2}}} = 1 s$

Therefore, the correct option is b: 1.0 s.

I hope it helps you!