An object with mass 5 kg is under constant force (10i+20j)N

[vipson231]

An object with mass 5 kg is under constant force (10i+20j)N...

Homework Statement

(Question is in the attachment)

For the question I used the equation F=ma= m Δ(Vf-vi)/t and plugged in 5 for m and for
velocity I put (vf -(-5+30)/10= (10i + 20j)N. My final equation was

(10i+20j)N= 5(vf-(-5+30)/10

This is as far as I got and I can't solve the question =(. Am i doing something wrong?

 

[Mandelbroth]

(10i+20j)N= 5(vf-(-5i+30j)/10
This is as far as I got and I can't solve the question =(. Am i doing something wrong?

Vector \equiv fun with a direction.
(10i + 20j) = 5(\vec{v}_{f}-(-5i + 30j))/10

Simplify...
(10i + 20j) = (1/2)(\vec{v}_{f}-(-5i + 30j))

Multiply vectors by the scalar
(10i + 20j) = (0.5)\vec{v}_{f}-(-\frac{5}{2}i + 15j)

Adding the "scaled" initial velocity vector to the other side
(10i + 20j) + (-\frac{5}{2}i + 15j) = (0.5)\vec{v}_{f}

Add vectors by components
(7.5i + 35j) = (0.5)\vec{v}_{f}

(15i + 70j) = \vec{v}_{f}

That's the third answer I see on the attachment, so I might have done this right.

 

[vipson231]

Thanks a lot man! :D