Question

Un cuerpo se lanza hacia arriba con 50 m/s . ¿A qué altura se encuentra cuando su rapidez es 20 m/s por segunda vez? (g = 10 m/s ^ 2) .

Answer 1

105 m

Step-by-step explanation:

Given that the initial velocity of the body, u= 50 m/s in upward direction.

Acceleration due to gravity, g= 10 m /
`s ^ 2` in the downward direction.

Let h be the height of the body when the velocity of the body is 20 m/s.

As the gravitational force acting in the downward direction, so taking it negative as

a= - 10 m/
`s ^ 2` in the upward direction.

By using the equation of motion
`v^2=u^2+2as` ...(i)

Here, u= 50 m/s

v= 20 m/s

`a=- 10 m/s^2`

s=h

Putting all the values in the equation (i), we have

`20^2=50^2+2(-10)h \\\\400=2500-20h \\\\h=(2500-400)/(20) \\\\h=105 m`

Hence, the height of the body is 105 m.