Question

If a ball is thrown in the air starting at position A (fromthe

ground) with an initial velocity of 80 m/s and given thatthe time
it takes to travel to point B is t=3s, What is theTime,
Displacement and Velocity at positions B (Half way up in theair), C
(At max height) and D (Back on ground).

Answer 1

Step-by-step explanation:

Given

initial velocity of ball at ground
`u=80 m/s`

Distance traveled in t=3 sec is given by

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

h=distance traveled

u=initial velocity

a=acceleration

t=time

`h=80* 3-(1)/(2)(-9.8)(3^2)`

`h=195.9\ m`

Maximum Height is obtained when final velocity

using
`v^2-u^2=2 ah`

where v=final velocity

`0-(80)^2=2* (-9.8)* h_(max)`

`h_(max)=(6400)/(2* 9.8)`

`h_(max)=326.53\ m`

time taken to reach maximum height

using
`v=u+at`

`0=80+(-9.8)\cdot t`

`t=(80)/(9.8)=8.16 s`

therefore total time will be twice of time required to reach at maximum height

time taken to reach point D is
`2* 8.16=16.32\ s`