The initial speed of a body of mass `2kg` is `5ms^(-1)` A force acts for `4` seconds in the direction of motion of the body. The force time graph is shown in Calculate impulse of the force and also find the speed of the body .
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Answer

`8.5 Ns ; 9.25 ms^(-1)` .

Explanation

Here, `m =2kg. U = 5ms^(-1) upsilon =` ?
Impulse = area under `F - t` graph
= area of Delt 0 ae + area of rect. Abfe + area of
trapezium bc gf + area of rect cdhg
` =(3 xx1.5)/(2) + 3 xx (2.5 -1.5)`
`+ ((3+2)/(2)) (3 - 2.5) + 2(4 -3)`
`=2.25 + 3 +1.25 + 2 = 8.5 Ns`
As Impulse = Change in momentum `= m (upsilon- u)`
`:. 8.5 = 2 (upsilon -5), upsilon = 8.5 Ns` .