The Textbook That Unleashed Ramanujan's Genius

Re:The Textbook That Unleashed Ramanujan's Genius by lqet on Wednesday May 19, 2021 @07:37AM (#27207192)

A bit off-topic, but I just googled some IIT-JEE questions and found the following:

  A large number of bullets are fired in all directions with same speed u. What is the maximum area on the ground on which these bullets will spread.

The provided answers all depend only on u, pi, and g.

How can this be possible? Obviously, if I fire the gun from a tower, this area will be larger than when I fire it from the ground, and thus also depends on the height above ground of the gun.

[ Parent | on HN ]

Re:The Textbook That Unleashed Ramanujan's Genius by flaubere on Wednesday May 19, 2021 @08:11AM (#27207477)

Not sure why you are asking this in this thread, but the implication is that the bullets are fired from ground level, not necessarily horizontally. The maximum distance a projectile can travel when fired from ground level is the basic first result of ballistics.

[ Parent | on HN ]

Re:The Textbook That Unleashed Ramanujan's Genius by tyleo on Wednesday May 19, 2021 @08:57AM (#27207929)

I think I understand. From height 0 figure out what gun angle gives the largest distance and then calculate the area of the circle with that distance as radius.

[ Parent | on HN ]

Re:The Textbook That Unleashed Ramanujan's Genius by xNeil on Wednesday May 19, 2021 @10:47AM (#27209401)

In the JEE, you generally assume the range to be the distance the projectile covers before reaching the launch height again, unless specified otherwise.

[ Parent | on HN ]

Re:The Textbook That Unleashed Ramanujan's Genius by xNeil on Wednesday May 19, 2021 @10:46AM (#27209378)

You have to assume the angle of projection is 45 degrees, in which case the range of the projectile becomes (u^2/g). (Since Range = (u^2)(sin2(theta))/g) Hope I helped!

[ Parent | on HN ]