Question

A body is dropped from a height of 30m. What is the velocity of the body after it has covered a distance of 20 m? (Given g= 10 m/s 2)

please fast

Answer 1

the velocity is 20m/s

Step-by-step explanation:

data given

1. Height (h)=20m
2. Gravity (g)=10m/s2
3. velocity v = 0
4. velocity u =?

`v2 = u2 - 2gh`

0 = u2 - 2 (10)(20)

0 = u2 - 400

400 = u2

20m/s = u

Answer 2

approximately 19.8 m/s

If using g = 10 m/s^2, the answer rounds to 20 m/s

Step-by-step explanation:

You can use the kinematic formula that relates distance covered, velocities and acceleration (without time dependence) given by:

`v_f^2-v_i^2=2\,*\,a\,*displacement`

which in our case becomes:

`v_f^2-0=2\,*\,(9.8\,(m)/(s^2)) \,*(20\,m)\\v_f^2=392\\v_f\approx 19.8\,(m)/(s)`

If using g = 10 m/s^2, the answer is 20 m/s