Question

you stand on a bridge above a river and drop a rock into the water below from a height of 53m (assuming no air resistance)

Answer 1

Given:

Height = 53 m

Given that the rock is dropped from the top of a bridge above the river, let's answer the following questions:

• (a). The acceleration of the rock as it falls.

Since the rock is in free fall, the acceleration of the rock as it falls will be the acceleration due to gravity.

a = 9.8 m/s²

Therefore, the acceleration of the rock as it falls is 9.8 m/s².

• (b). How long does it take to hit the water?

To find the time, apply the formula:

`s=ut+(1)/(2)at^2`

Where:

s = 53 m

t is the time

a is the acceleration

u is the initial velocity = 0 m/s

Let's solve for the time, t:

`\begin{gathered} 53=0(t)+(1)/(2)*9.8*t^2 \\ \\ 53=4.9t^2 \\ \\ t^2=(53)/(4.9) \\ \\ t=√(10.82) \\ \\ t=3.29 \end{gathered}`

Therefore, the time is 3.29 seconds.

(c). If the rock is dropped horizontally instead, there will be no change in the vertical velocity.

The time will also not change.

The time will be 3.29 seconds

ANSWER:

(a). 9.8 m/s^2

(b). 3.29 seconds

(c). 3.29 seconds