Question #ab83f

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Answer 1 · 2016-08-24T08:21:25

Let

$"East"-> +"ve direction of x-axis"$

$"West"->-"ve direction of x-axis"$

$"North"-> +"ve direction of y-axis"$

$"South"->-"ve direction of y-axis"$

$vec(V_i)->"Initial velocity vetor"$

$vec(V_f)->"Final velocity vetor"$

$abs(vec(V_i))=8.5m/s$

$abs(vec(V_f))=19m/s$

$t->"Time of change of velocity"=2s$

$"Direction of "vec(V_i)=S42^@W=(270-42)^@$

$"Direction of "vec(V_f)=W35^@N=(180-35)^@$

$vec(V_i)=8.5(cos(270-42)hati+sin(270-42)hatj)$
$=-8.5(sin42hati+cos42hatj)$
$=-5.69hati-6.32hatjm/s$

$vec(V_f)=19(cos(180-35)hati+sin(180-35)hatj)$
$=19(-cos35hati+sin35hatj)$
$=-15,56hati+10.9hatjm/s$

$"Now average acceleration"$
$vec(a)=(vec(V_f)-vec(V_i))/t$

$=1/2(-9.87hati+17.22hatj)ms^-2$

$abs(vec(a))=1/2sqrt(9.87^2+17.22^2)~~19.85ms^-2$