## anonymous one year ago An air-track glider of mass 0.25 kg moving at 0.60 m/s collides with and sticks to a glider of mass 0.50 kg at rest. How much kinetic energy is converted into other forms of energy as a direct result of this collision? A. 0.030 J B. 0.045 J C. 0.015 J D. 0.060 J ***not sure at all! :( Thank you!! :D

1. Michele_Laino

here we have to apply the conservation of momentum, so we can write: $\Large {m_1}{v_1} = \left( {{m_1} + {m_2}} \right)u$

2. anonymous

okay!

3. Michele_Laino

where m_1= 0.25 Kg, m_2=0.50 Kg, and v_1=0.60 m/sec

4. Michele_Laino

u is the final speed of the system particle1+ particle2

5. Michele_Laino

we have to find what is u: $\Large u = \frac{{{m_1}{v_1}}}{{{m_1} + {m_2}}} = ...m/\sec$

6. anonymous

okay, so i plug in like this? (0.25*0.60)=(0.25+0.50)u so like this? 0.15=0.75u u=0.2 ?

7. anonymous

oh oops

8. anonymous

oh wait... it is 0.2, correct? the value of u?

9. Michele_Laino

that's right u=0.2 m/sec

10. anonymous

okay! what happens next?

11. Michele_Laino

Now the final kinetic energy is: $\Large {E_f} = \frac{1}{2}\left( {{m_1} + {m_2}} \right){u^2} = ...Joules$

12. anonymous

okay! so 1/2(0.25+0.50)0.2^2 = 0.015 J ? so the answer is 0.015 J? :O

13. Michele_Laino

that's right!

14. anonymous

yay!! thank you:D

15. Michele_Laino

whereas the initial kinetic energy is: $\Large {E_i} = \frac{1}{2}{m_1}v_1^2 = ...Joules$

16. Michele_Laino

@iheartfood

17. anonymous

ahh so it would be 1/2(0.25+0.5^2)? so 0.25 is the initial kinetic energy?

18. Michele_Laino

I got 0.045 Joules

19. Michele_Laino

$\Large {E_i} = \frac{1}{2}{m_1}v_1^2 = \frac{1}{2} \times 0.25 \times {\left( {0.6} \right)^2} = ...Joules$

20. anonymous

ohhh yes 0.045 sorry, i plugged in the wrong thing! wait so for this problem, i now have to do this to find the answer? 0.045-0.015=0.030 J ? and that would be this problem's final solution? :O

21. Michele_Laino

yes! That's right!

22. anonymous

yay!! and so this problem is completed now? :O

23. Michele_Laino

yes! We have finished!

24. anonymous

yay!! thank you:D

25. Michele_Laino

thank you!! :D