M1 Forces question.

Anyone wanna help me on this?
Its from the Jan 06 Paper:

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.

:woo:

Reply 1

DoMakeSayThink

15

Have you drawn a diagram?

Try expressing both Q and the resultant force as their components in the North and East (i and j) directions.

Reply 2

*Princess*

Golgi_Body

Anyone wanna help me on this?
Its from the Jan 06 Paper:

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.

:woo:

See the diagram please

in the x direction the force component is 10sin60=8.66
y direction, 10cos60=5

to find the magnitude square 8.66 and 5 then add them up
8.66^2 + 5^2= 100
then square root 100= 10

so magnitude is 10N

hope this helps
please feel free to correct me if this is wrong

Golgi_Body

Anyone wanna help me on this?
Its from the Jan 06 Paper:

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.

:woo:

The Princess person was wrong ^

Its cosine rule, have a look at this diagram

Use cosine rule with b = 10, c= 10 and A = 120, and you get a = 14.8 (3s.f.), so Q = 14.8N

Then sine rule with a = 14.8, A = 120, b = 10, B = x, and you get 35
degrees, take this from 108 to get the bearing of 144.