## ashna 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. ashna

@akash123

2. akash123

find out the change in momnetum

3. akash123

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

4. akash123

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

5. akash123

does it make sense?

6. ashna

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. akash123

change in momentum= (final momentum- initial momentum)

8. Yahoo!

1st find accl

9. akash123

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

10. akash123

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

11. Yahoo!

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

12. Yahoo!

$F= Ma$

13. akash123

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

14. Yahoo!

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

15. akash123

no need to calculate change in the momentum

16. Yahoo!

hope this helps

17. Yahoo!

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

18. ashna

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

19. ashna

am sry i din see that .. am sry !

20. Yahoo!

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

21. akash123

:)