Question

Virtual Lab: Ballistic Pendulum Introduction The ballistic pendulum was invented by Benjamin Robins in 1742 as a device mainly designed to accurately measure the speed of fast traveling projectiles (bullets or cannon balls), relying only on measurements of mass and distance, without measurements of time. Knowing the mass of the projectile, estimates of its momentum and kinetic energy could also be made. Although the ballistic- pendulum method has lost its practical importance to more modern methodologies, it was used for a long time to advance the science of ballistics, and it is still useful today in classrooms to demonstrate basic properties of speed, momentum, and energy In the simplest configuration, a ballistic pendulum consists of a wooden block of mass m, suspended on a piece of string. A projectile of mass m is horizontally fired at the block and embeds itself in the block This causes the combined block-plus-projectile system to swing up a height y. The initial speed of the projectile before it hits the block can be estimated using the expression mm 2 gy The JavaScript provided with this document simulates a ballistic pendulum. It allows a user to change the initial speed of the projectile v, and the masses m and m, of the projectile and the block, respectively. The simulation also shows the vertical coordinate y of the block as it is swinging up and down after the projectile collides with it (see the yellow box at the bottom right comer). Get familiar with running the simulation by changing the different available setting and controls, and observe their effects.

Answer 1

CIASSMAte Problem ③ AS There is no You Theoretical experimental date, explainations a can only give into Block + projectile move important points IM Block Projectile/ Bullet As bullet gets embedded wooden Block collision es perfectly melastic il only momentum in conserved and Kinetic Energy is lost partially (not conserved) mvp = (m+ M) VE After collision with a velocity Here conservation of Energy is applied 1 Gravitational PE gain intial kinetic Energy I which is kinetic Energy Just after cottion] (M + migh 2 (M + m) V ² [ Block & Projectile) from 0 & calculate up from {bor Y ? v and so we can Uf = /2 gb putting this value in 0 (height By which Block & Bullet sises) VpE mt M Vagh m kinetic Energy As Collision is perfectly melastic of Bullet / projectile is not completely transfered to Block-projectile system and KE es lost in this collision

Block t Same as projectile after collision will not have KE Bullet ( will have lesser). Max Max KE projectile Max > KE of (Block & Projectile) = PE of (Just Before collision) (Just after collision] Block + project Max kЕ projectile Potential Energy) So Max PE Cgravitational on is Momentum is always conserved if there no External force acting system momentum of Bullet just Before collision equal to (within experimental emor) momentum of Block & Ballet system just in the case Offer collision