/sci/ - Science & Math

[Anonymous No.2881137]

Anyone wanna help me on this?


Q4) Two Forces P and Q act on a particle. The force P has magnitude 7N and acts due north. The resultant of P and Q is a force magnitude 10N acting in direction with beaing 120o. Find:

i) The magnitude of Q
ii) The direction of Q giving your answer as a bearing.

mag of q is 14.8 + = 8.66i - 12j

i) was piss easy but i dont get ii for shit. ive tried using tan -1 12 / 8.66 but i cant get it

been on this for over an hour

(1 hour 22 to be precise)

any help? :(

[Anonymous No.2881175]

bump

[Anonymous No.2881181]

Just subtract P from (P+Q) to get Q.

[Anonymous No.2881186]

Ok, draw Q. It's headed vaguely SEish, right?

Stick the unit vectors on and make it a triangle. 8.66 across the top, 12 down the right hand side.

The angle of interest is opposite 12, adjacent to 8.66, so is atan(12/8.66) = 54 degrees. But the angle starts at 90 degrees, so add 54 to 90 to get 144 degrees.

Hope you're good?

[Anonymous No.2881187]

ty for reply bro.

but i needed to know how to work out the direction of q?

in simple terms how2work out direction of a vector?? the answers 144 defrees

[Anonymous No.2881193]

>>2881137

holy shit i fucking love you

i hate it when you spend so long on something then its this easy.

now my whole days pretty much wasted as i could have done another m1 paper in that time :(

Thanks so much bro <333333