## zaphod 3 years ago A particle of mass 5kg is pulled along a smooth horizontal surfce by a horizontal string> if the acc of particle is 3ms-2find the tension

1. zaphod

@Callisto can i kw hw to apply the forces?

2. Callisto

|dw:1347114640040:dw| Consider the horizontal, Summation F = T = ma = 5(3), isn't it?

3. Callisto

|dw:1347114778579:dw| The vertical forces cancel out..

4. Callisto

Note that smooth = friction = 0N Note sure if I'm in the right direction :|

5. zaphod

yes |dw:1347114907153:dw|

6. Callisto

Why did you add that T?

7. zaphod

in a horizontal string tension acts oppostely

8. Callisto

Hmm.. I'm actually considering this part..|dw:1347115073162:dw|

9. zaphod

yes then continue?

10. Callisto

For that system, weight is balanced by the normal reaction. So, vertical forces cancel. Consider the horizontal force, since the surface is 'smooth', there is no friction acting on the particle. The only horizontal force acting on the system is tension. So, by Newton's 2nd law, T - f = ma , where f = 0, m=5 and a=3 So, you can find T.

11. Callisto

f= 0N, m=5kg and a=3ms^-2

12. zaphod

:) get it why is force = 0

13. keily

Tension=5kg times 3m/s=15N

14. Callisto

f is friction acting on the system by the surface. But the surface is smooth, so no friction acting on the system

15. Callisto

Any questions?

16. zaphod

nope clear :)

17. Callisto

Great!

18. zaphod

i thought there is an external force making the particle move, anyway nw i understnd

19. Callisto

That external force is the tension. If you don't pull the string, there is no tension, the block doesn't move. Perhaps you can consider that system only. I mean the force applied to that system.

20. zaphod

yes thanks u so much :)

21. Callisto

Welcome :)