Question

A stone is thrown down off a bridge with a velocity of 7.2 m/s what is its velocity after 4 seconds

Answer 1

The speed after 4 seconds is 46.4 m/s

Step-by-step explanation:

Vertical Launch Downwards

In a vertical launch downwards, an object is launched vertically down from a height H without taking into consideration any kind of friction with the air.

The final speed is calculated by using the formula:

`v_f=v_o+g.t`

Where:

vf = Final speed

vo = Initial speed

g = Acceleration of gravity (9.8~m/s^2)

t = Elapsed time

The stone is thrown down off a bridge at vo=7.2 m/s. We need to calculate the speed after t=4 seconds.

Substituting:

`v_f=7.2~m/s+9.8~m/s^2*4~s`

Calculating:

`v_f=46.4~m/s`

The speed after 4 seconds is 46.4 m/s