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Grade 11General Physics

The maximum range of a gun on horizontal surface is 16km. If g=10 ms-2, the muzzle velocity of the shell must be:-
a. 1600 ms-1 b. 400 ms-1 c. 200 (root2 ) ms-1 d. 160(root 10) ms-1

​I want the answer with full solution

Profile image of Ananya Sharma
10 Years agoGrade 11
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2 Answers

Profile image of Akshay
ApprovedApproved Tutor Answer10 Years ago
maximum range will be when gun is shot at 45 deg.
Lets prove this fact first, assume that gun is shot at angle a with horizontal with velocity v,
U = (v.cosa) i + (v.sina) j
s=U*t+0.5*a*t2 ,
a= – 10 j,
s = (v.cosa*t) i + (v.sina*t – 5.t2) j,
final y-coordinate will be 0,
so , t=v.sina / 5,
Range = v.cosa.t = v2.cosa . sina / 5 = v2 . sin2a /10,
maximum range will be when sin2a = 1, or a=45,
Max range =  v2 / 10 = 16000,
So v=400 m/s
Profile image of Anjali yadav
8 Years ago
The horizontal range will be maximum if the bullet is fired at an angle of 45° to the horizontal. We have, R=u^2*sin2β/g Since the angle is 45°,soR=u^2*(sin2*45°)/gor, R=u^2/gAlso, R=16km=16000mAnd, g=10m/s^2So, 16000=u^2/10or, u^2=16000*10or, u=√160000Therefore, u=400m/s Hope you understand this😊😊