Question

A force of 2i+7j N acts on a body of mass 5kg for 10 seconds. The body was initially moving with constant velocity of i−2j m/s. Find the final velocity of the body in m/s, in vector form.

Having problem solving with vectors...

Answer 1

isnt it just the adding of the two vectors?

Answer 2

my first thought was dot product; but that doesnt result in a vector does it

Answer 3

m1v1+m2v2 = (m1+m2)v3 .... is something that might apply

Answer 4

F=ma
a=(v_f-v_i)/t

Answer 5

yes, the formula is F = m(v2-v1)/t but the vectors are my problem because the answer is to be given in the vector form

Answer 6

shivams looks eloquentier to me

Answer 7

10F/m +v1 = v2

Answer 8

@amistre64
Ft/m = v_f - v_i

Answer 9

@amistre64 , I wanted to say is this new word-eloquentier ??

Answer 10

10<2,7>
-------- + <1,-2> = Vf
2

Answer 11

lol, might be new; if so i might as well patent it :)

Answer 12

See. vector subraction

A vector = x i + y j +z k
B vector = p i + q j + rk
B-A = (p-x) i + (q-y) j + (r -z) k

Answer 13

i never did care much for the ijk format

Answer 14

how does the N play into the picture? that Newton?

Answer 15

@amistre64 , @Prof.Grace is new to this. let him get used to this. Later he can easily learn what you are trying to convey :D

Answer 16

F is vector and newton is unit of F

Answer 17

@Prof.Grace , any problem now with vector addition and subtraction??

Answer 18

should Vi be converted to a Netwon equivalent?

Answer 19

No. Because Ft/M is m/s

Answer 20

hmm, looks good to me then. Math i can handle, trying to physicate ... not so much :)

Answer 21

@amistre64 , Maths and physics are always inter-related :D

Answer 22

i think i've gotten the answer, thanks y'all..

Answer 23

Good luck :D

Answer 24

If you were given a constant acceleration and the time and also the initial velocity, you could find final velocity by v=u+at. You can do the exactly same thing for vectors as well as I’ve explained below.
Divide the vector force F with the scalar mass to get the accelaration vector. Multiply this with time to get the change in velocity vector. Add this vector to the original velocity vector. And you've got the final velocity vector.
acc vector a= (2i+7j)/5 m s-2
change in velocity δv= (2i+7j)/5 m s-2 * 10s =4i+14j m s-1
Add this to the original velocity vector.