A body of mass 0.40 kg moving initially with a constant speed of 10 m s^(-1) to the north is subject to a constant force of 8.0 N directed towards the south for 30 s.Take the instant the force is applied to bet = 0, the position of the body at that time to be x = 0, and predict its position att = –5 s, 25 s, 100 s.

A body of mass 0.40 kg moving initially with a constant speed of 10 m

1.	A body of mass 0.40 kg moving initially with a constant speed of 10 m s^(-1) to the north is subject to a constant force of 8.0 N directed towards the south for 30 s.Take the instant the force is applied to bet = 0, the position of the body at that time to be x = 0, and predict its position att = –5 s, 25 s, 100 s.
Answer» Solution :u = `10 ms^(-1)` m= 0.40kg (Northdirection) t=30 s Herenorthdirectionis consideredas POSITIVEAND southdirectionisconsideredas negative Forceis appliedfor t=30 s (i) At t=5 sposition `X_(1) = ut` `=10xx (-5)` (ii)at t=25 s `x_(2)ut + (1)/(2)4r^(2)` where`a = (F )/( m ) =(-8)/(0.4)= - 20ms^(-2)` `=250- 6250` `-=6 km` when forceis appliedfor 30s distancecovered velocityof objectafter30 s = u+ 9t =10 -600 (III)Positionof objectat t=100s `:.x_(100)= x_(30) a + x_(70)` =-870041300 `=-5000 m` `=-50 km` Thuspositionat -5 s 25 s and 10 willbe-50 m-6 kmand-50 km