Question

A student throws a rock horizontally off a 5.0 m tall building. The rock's initial speed is 6.0 m/s. How long will it take the rock to reach the ground? Air resistance is negligible.'

Answer 1

Answer:

The time taken by the rock to reach the ground is 0.569 seconds.

Explanation:

Given that,

A student throws a rock horizontally off a 5.0 m tall building, s = 5 m

The initial speed of the rock, u = 6 m/s

We need to find the time taken by the rock to reach the ground. Using second equation of motion to find it. We get :

$s=ut+\dfrac{1}{2}gt^2\\\\5=6t+\dfrac{1}{2}\times 9.8t^2\\\\t=0.569\ seconds$

So, the time taken by the rock to reach the ground is 0.569 seconds. Hence, this is the required solution.

Answer 2

Answer:

The rock to reach the ground in 0.569 sec.

Explanation:

Given that,

Height = 5.0 m

Speed = 6.0 m/s

A student throws a rock horizontally off a 0.5 m tall building.

This is the distance.

So, s = 0.5 m

We need to calculate the time

Using equation of motion

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

Where, s = distance

t = time

g = acceleration due to gravity

Put the value into the formula

$5.0=6.0\times t+0.5\times9.8t^2$

$4.9t^2+6.0 t-5.0 =0$

$t = 0.569\ sec$

Neglect the negative value.

Hence, The rock to reach the ground in 0.569 sec.