Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 11-science Answered

A shell burst on contact with the ground. The fragment fly in all directions with speed up to 30 m/ s . A man standing at a distance of 45 m is in danger for ________ seconds . 
Assume g = 10 ms
Asked by nilesh | 24 Jul, 2015, 11:10: PM
answered-by-expert Expert Answer
Given that: u = 30 ms-1 and R = 45 m
begin mathsize 12px style Horizontal space range comma space straight R space equals space fraction numerator straight u squared sin 2 straight theta over denominator straight g end fraction rightwards arrow 45 equals space fraction numerator left parenthesis 30 right parenthesis squared sin 2 straight theta over denominator 10 end fraction Or space sin 2 straight theta space equals space fraction numerator left parenthesis 30 right parenthesis squared cross times space 45 over denominator 10 end fraction Or space sin 2 straight theta space equals 1 half Or comma space 2 straight theta space equals space 30 degree space or space 150 degree Or comma space straight theta space equals space 15 degree space or space 75 degree This space gives space two space times space of space flight comma space say space straight t subscript 1 space and space straight t subscript 2 rightwards arrow straight t subscript 1 space equals space fraction numerator 2 usin 15 degree over denominator straight g space end fraction space and space straight t subscript 2 space equals space fraction numerator 2 usin 75 degree over denominator straight g space end fraction The space difference space between space the space two space times space of space flight space will space the space time space for space which space the space man space will space be space in space danger. That space is comma space the space man space will space be space in space danger space for space left parenthesis straight t subscript 2 minus straight t subscript 1 right parenthesis rightwards arrow space left parenthesis straight t subscript 2 minus straight t subscript 1 right parenthesis equals space space fraction numerator 2 usin 75 degree over denominator straight g space end fraction space minus space fraction numerator 2 usin 15 degree over denominator straight g space end fraction space space space space space space space space space space space space space space space space space equals space fraction numerator 2 straight u over denominator straight g end fraction left parenthesis sin 75 degree space minus space sin 15 degree right parenthesis space space space space space space space space space space space space space space space space space equals fraction numerator 4 straight u over denominator straight g end fraction left parenthesis sin 30 degree space cos space 45 degree right parenthesis space space space space space space space space space space space space space space space space space space equals fraction numerator 4 space cross times space 30 over denominator 10 end fraction space cross times space 1 half space cross times space fraction numerator 1 over denominator square root of 2 end fraction space space space space space space space space space space space space space space space space space equals 3 square root of 2 end style
Answered by Yashvanti Jain | 15 Dec, 2017, 07:29: PM

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 11-science - Physics
7. State the relation between maximum range and maximum height of the projectile if the angle of projection is 45 deg
Asked by roshnibudhrani88 | 23 Mar, 2024, 05:52: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
A platform is moving upwards with an acceleration of 5m/s².At the moment when it's velocity is 3m/s, a ball is thrown from it with a speed of 30m/s w. r. t platform at an angle of 30 with horizontal w. r. t plat form. What is the time taken by the ball to return to the platform
Asked by shailajakandikatla19 | 18 Jan, 2024, 06:40: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
A particle is projected from a point P with a velocity v at an angle θ with horizontal. At a certain point Q it moves at right angles to its initial direction. Then (a) velocity of particle at Q is vsintheta (b) velocity of particle at Q is Vtantheta (c) time taken from P and Q is v/g sin theta (d) time taken from P and Q is v/gsectheta
Asked by hy9022075 | 11 Jan, 2023, 05:06: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
A baseball is hit by a bat and given a velocity of 40.0m/s at an angle of 30 degree above the horizontal. The height of the ball above the ground upon impact with the bat is 1.0 m  a) what maximum height above the ground does the wall reached b) a feilder is 110.0 m from home plate with the ball is hit and the balls trajectory is directly at home if he begins running at the moment the ball is hit and catches the ball. when it is still 3.0 m above the ground. How long does he run before catching the ball. C) how fast does he have to run in order to catch the ball
question image
Asked by lonese3325 | 12 Jun, 2022, 01:42: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
A particle of mass m is given speed u at angle theta at topmost point It breaks into two equal parts one comes to rest  find point of landing of second mass
Asked by ashishgarud539 | 15 Dec, 2021, 04:12: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
a projector is projected horizontal with velocity 10 ms making distance 45 degree .what is time of flig
Asked by Kalapnadevi0000 | 14 Apr, 2021, 03:06: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
what is the meaning of projectile motion
Asked by riyag9034 | 26 Jul, 2020, 07:06: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
If a ball launched with initial velocity of 25 m/s at 45 degree. Find the maximum range covered by the ball? 
Asked by sehgalgayrav810 | 29 May, 2020, 07:19: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
Pls solve
question image
Asked by suchananag2002 | 27 Feb, 2020, 09:48: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 11-science - Physics
what is lowest speed of an object in the projectile motion fired with an angle 30º and speed is 5m/s?
Asked by nirvardhansinghranawat7773 | 11 Oct, 2019, 01:27: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×