Question

An object i dropped from ret and fall freely 20. Meter to Earth. When i the peed of the object 9. 8 meter per econd?

Answer 1

The speed of the object is 9.8 meters per second after one second of free fall. In that one second, the object travels 4.9m.

Step-by-step explanation:

On Earth, acceleration due to gravity is 9.8
`(m)/(s^2)`. Use kinematic equation #1 to find the time it takes this object to achieve the given speed (v).

`v=v_0+at\\a=9.8(m)/(s^2)\\v_0=0(m)/(2)\\v=9.8(m)/(s)\\9.8(m)/(s)=0.0(m)/(s)+(9.8(m)/(s^2))t\\t=\frac{9.8(m)/(s)}{9.8{m}{s^2}}\\t=1 s`

This is intuitive. The velocity of an object in free fall gains 9.8
`(m)/(s)` per second unless acted upon by an outside force.

To find how far the object has fallen, insert the given and derived values into kinematic equation #2.

`\Delta y=((v+v_0)/(2))t\\\Delta y=((9.8(m)/(s)+0.0(m)/(s))/(2))(1 s)\\\Delta y=4.9m`

Hope that helps.