MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: R

There are no items in this cart.
Continue Shopping
Menu
Mohammed faisal anees Grade: 11
        

A bullet loses 1/20 of its velocity after penetrating into a plank. How many planks are required to stop the bullet ?

6 years ago

Answers : (2)

Prudhvi teja
83 Points
										

Dear mohammod


Let the thickness of one plank = d
and the acceleration provided by the plank = a

v^2 = vo^2 + 2ad
If n planks are required to stop the bullet, then
0^2 = vo^2 + 2a*nd
2and = -vo^2
n = vo^2/(-2ad) -----------------(1)

v = vo - vo/20 = 19 vo/20 in passing through one plank
(19 vo/20)^2 = vo^2 + 2ad
361/400 * vo^2 = vo^2 + 2ad
-2ad = vo^2(1 - 361/400)
-2ad = vo^2 * 39/400

Substituting this value of -2ad into equation (1):
n = vo^2/(vo^2 * 39/400) = 400/39
The minimum number of planks needed = smallest integer greater than 400/39 = 11
Ans: 11


 



Please feel free to post as many doubts on our discussion forum as you can.we will get you the answer and detailed  solution very  quickly.

All the best.


Regards,
Askiitians Experts
Prudhvi Teja


 


 



Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian


6 years ago
vikas askiitian expert
510 Points
										

applying v^2=u^2+2ad  ,here d is the width of plank


 v=u/20 after penetrating 0ne plank


  2ad=399u^2/400 .........eq1 


  for n number of planks total distance after which bullet stops is nd


 again applying v^2=u^2+2adn  and putting v=0


  n=u^2/2ad......eq2


 solving 1and 2 


   n=1

6 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies
  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 4,500 off
USE CODE: SSP3
  • Kinematics & Rotational Motion
  • OFFERED PRICE: R 600
  • View Details
Get extra R 120 off
USE CODE: MOB20

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!! Click Here for details