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Newtons 1st law helpppp pleasee watch

1. Hi everyone, im fully content with the other two laws, but dont seem to understand the first one properly....how can all the forces on an object be in equilibrium and it still be able to move?... i though when they are in equilibrium it would stand still????

im not sure if im a total numpty, any helpp????
2. It basically says that an object will remain at constant velocity or remain stationery unless a net force acts on it....I think

Which is basically if you are running at 10m/s unless a force acts on you , you'll stay running at 10m/s so if there's a massive strong wind pushing towards you you may go faster at like 11m/s. Does it make sense. Its the same thing with stationery objects.

You hav a pen on a table it will stay still the net force will be you pushing the pen so it moves

You dont really neef to understand what they mean just to be able to recall them in an exam
3. I need help understanding suvat equation.
I never know which one to use
4. If the object is stationary and the net force is 0 then it won't move. However if the object is already moving and the net force is 0 (in equilibrium) then the object will carry on moving at a constant speed as a force is needed to change velocity. Therefore if the forces are not balanced the object would then accelerate - I think that's it
5. (Original post by Aneesah_May)
I need help understanding suvat equation.
I never know which one to use
break down the question. in a suvat

s= displacement
u= initial velocity
v= final velocity
a= acceleration
t= time

read the question and work out what it want you to find and what it has given you. for example if it has given you s, u and t and wants you to find a choose the equation which doesn't involve v (as it is irrelevent to the question). then rearrange to make v the subject.

hope this helps
6. (Original post by MidnightDream)
If the object is stationary and the net force is 0 then it won't move. However if the object is already moving and the net force is 0 (in equilibrium) then the object will carry on moving at a constant speed as a force is needed to change velocity. Therefore if the forces are not balanced the object would then accelerate - I think that's it
hi, yes its just how can something be already moving if the net force is zero dont you need force for meovement in the 1st place?
7. (Original post by Aneesah_May)
I need help understanding suvat equation.
I never know which one to use
v=u+at (when you have no s - displacement)
s=ut+1/2at^2 (when you have no v - final velocity)
s=vt-1/2at^2 (when you have no u -initial velocity)
v^2=u^2+2as (when you have no t - time)
s= (u+v)/2 x t (when you have no a - acceleration)
8. (Original post by salaama)
hi, yes its just how can something be already moving if the net force is zero dont you need force for meovement in the 1st place?
To start moving the net force is not zero. However the forces may balance out whilst the object is moving. So like friction will equal the forward force

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Updated: January 21, 2014
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