Question

A ball falls straight down through the airunder the influence of gravity. There is aretarding force vector F on the ball with magnitude given byF=b v, wherevis the speed of theball andbis a positive constant. What is the magnitude of the acceleration of the ball at time t/2?

Answer 1

So as we know,

`F_1=bv`

However at the fall, there is two more Force

`F_2 = mg` (Gravity)

`F_3 = ma`(Net force)

So,

`F_3 = F_2 - F_1`

`ma = mg -bv`

`a= g-(bv)/(m)`

For t/2

`a(t/2) = g- (b*(x)/(t/2))/(m)`

`a(t/2) = g-2(bx)/(mt)`