Let
"East"-> +"ve direction of x-axis"East→+ve direction of x-axis
"West"->-"ve direction of x-axis"West→−ve direction of x-axis
"North"-> +"ve direction of y-axis"North→+ve direction of y-axis
"South"->-"ve direction of y-axis"South→−ve direction of y-axis
vec(V_i)->"Initial velocity vetor"→Vi→Initial velocity vetor
vec(V_f)->"Final velocity vetor"→Vf→Final velocity vetor
abs(vec(V_i))=8.5m/s∣∣∣→Vi∣∣∣=8.5ms
abs(vec(V_f))=19m/s∣∣∣→Vf∣∣∣=19ms
t->"Time of change of velocity"=2st→Time of change of velocity=2s
"Direction of "vec(V_i)=S42^@W=(270-42)^@Direction of →Vi=S42∘W=(270−42)∘
"Direction of "vec(V_f)=W35^@N=(180-35)^@Direction of →Vf=W35∘N=(180−35)∘
vec(V_i)=8.5(cos(270-42)hati+sin(270-42)hatj)→Vi=8.5(cos(270−42)ˆi+sin(270−42)ˆj)
=-8.5(sin42hati+cos42hatj)=−8.5(sin42ˆi+cos42ˆj)
=-5.69hati-6.32hatjm/s=−5.69ˆi−6.32ˆjms
vec(V_f)=19(cos(180-35)hati+sin(180-35)hatj)→Vf=19(cos(180−35)ˆi+sin(180−35)ˆj)
=19(-cos35hati+sin35hatj)=19(−cos35ˆi+sin35ˆj)
=-15,56hati+10.9hatjm/s=−15,56ˆi+10.9ˆjms
"Now average acceleration"Now average acceleration
vec(a)=(vec(V_f)-vec(V_i))/t→a=→Vf−→Vit
=1/2(-9.87hati+17.22hatj)ms^-2=12(−9.87ˆi+17.22ˆj)ms−2
abs(vec(a))=1/2sqrt(9.87^2+17.22^2)~~19.85ms^-2∣∣→a∣∣=12√9.872+17.222≈19.85ms−2