## anonymous 3 years ago A bullet of mass 20g moving with a speed of 150m/s atrikes a block and comes to rest after piercing 10cm into it . Find the avg. force of resistance offered by the block.

1. anonymous

@akash123

2. anonymous

find out the change in momnetum

3. anonymous

then average force of resistance= rate of change of momentum= (change in momentum)/ (time interval)

4. anonymous

so 1st u have to calculate..how much time bullet will take in coming to rest?

5. anonymous

does it make sense?

6. anonymous

i guess i dont understand , sorry akash am slow in this , and i want you to help me , how to calculate change in momentum ?

7. anonymous

change in momentum= (final momentum- initial momentum)

8. anonymous

1st find accl

9. anonymous

i mean... 1st the bullet was moving with a speed of 150m/s then its momentum = m(150), m=20g

10. anonymous

yes use the formula v^2- u^2= 2as

11. anonymous

$V^2 - u^2 = 2as$ $\frac{ 150*150*100 }{ 2*10 } = a$

12. anonymous

$F= Ma$

13. anonymous

if u find the acceleration, then u can calculate the average resistance force by multiplying acceleration with mass

14. anonymous

Note mass shuld be in kg 1 gm = 10^-3 kg

15. anonymous

no need to calculate change in the momentum

16. anonymous

hope this helps

17. anonymous

According to COD ...this is maths page...and u r asking physics...Question....Plzzz...Go..to physics page

18. anonymous

okay let me try , @akash123 and @Yahoo! thank yu !

19. anonymous

am sry i din see that .. am sry !

20. anonymous

No...Problem.....and welcomee...

21. anonymous

:)