1800-150-456-789
FlagBACK
Flag Modern Physics> Please help me with sum 15 16 and 17 of t...
question mark

Please help me with sum 15 16 and 17 of the attached imagePlsss

Unknown guy , 7 Years ago
Grade 11
anser 3 Answers
Eshan

Last Activity: 6 Years ago

Dear student,

Please post one question per thread only,

Answer to question number 15-

Let the height of point from ground where they meet behand time after which they meet bet.

Hence for first ball,100-h=\dfrac{1}{2}gt^2

For the second ball,h=25t-\dfrac{1}{2}gt^2

Adding the two gives, t=4s, h=20m

Venkat

Last Activity: 6 Years ago

Take height from the top as x
 
When dropped from top , u = 0, g = 9.8 , h = x, time taken is t
x=ut+0.5gt2 = 0 + 0.5(9.8)t2= 4.9t2   (1)
 
When the  ball projected upward, h = 100-x , u = 25 m/s , time is same t
100-x = 25 t-0.5*9.8*t2
x = 100-25t+4.9t2 (2)
 
from (1) and (2)
4.9t2 = 100-25t+4.9t2
t = 100/25 = 4 seconds
 
From (1)
x= 4.9(4)2    = 78.4 meters

Aman

Last Activity: 6 Years ago

For 14
Let height reached by particle on the top of building be x
Initial velocity u= 14m/s
And final velocity v =0
As v= u+at
v= u- gt
t= 1.42s
As h= ut -1/2gt2 
h = 14×1.42- 1/2 ×10×1.42×1.42
   = 19.88- 10.08
    = 9.8m
Given total time taken= 4.6s
Time left 4.6-1.42= 3.18s
Second case::
Velocity at heighest point is zero
u=0
v =? 
t=3.18s
v= 9.8×3.18= 31.164m/s
2as= v2 - u2
s= (31.164×31.164)/2×9.8
  = 49.55m
Total height = 49.55m
Height of building = 49.55-9.8
  = 39.7m
 
 
 

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...

Other Related Questions on modern physics

question mark
A particle is projected in vertical plane such that after 5 seconds its velocity becomes horizontal. The maximum height attained by the projectile from point of projection is n3 m. The value of n is _______. (g = 10 m/s2)
modern physics
1 Answer Available

Last Activity: 2 Years ago

question mark
Two particles approach each other from very large distance as shown, . if the least separation between the particles is b, what is the speed of M in center of mass frame when particles are closest? (gravity negligible)
modern physics
0 Answer Available

Last Activity: 2 Years ago

question mark
Can the sum of two equal vectors be equal to either vector
modern physics
0 Answer Available

Last Activity: 2 Years ago

question mark
A nucleus X184 at rest emitt alpha particle With kinetic energy 9.0MeV. The product Nucleus is Y. The values of Binding energy per nucleon of alpha particle & Y differ by 1.5MeV. The values of Binding energy per nucleon of X & Y differ by (n÷230) MeV, then n is
modern physics
0 Answer Available

Last Activity: 2 Years ago

question mark
SUBJECT: PROBLEM BASED ON LINE DETECTION.Query: How to apply all the filters for line detection on the following piece of image (provided below)? Explain its Observations to comment on its results.
modern physics
0 Answer Available

Last Activity: 2 Years ago