A projectile with a mass of 0.14 kg is fired at and embeds itself in a stationar
ID: 1612535 • Letter: A
Question
A projectile with a mass of 0.14 kg is fired at and embeds itself in a stationary target with a mass of 2.90 kg. The target and embedded projectile fly off after being struck. Determine the percent of the projectile's incident kinetic energy carried off by the target- projectile combination. Enter a number, conservation of momentum to determine an expression for the target-projectile combination after the collision In terms of the initial speed of the projectile and the messes of the projectile and target. Following this, you can write an expression for the initial kinetic energy and the final kinetic energy (in terms of the initial kinetic energy) and then determine the percent of the projectile's incident kinetic energy carried off by the target-projectile combination.%Explanation / Answer
m = mass of lighter projectile = 0.14 kg
v = initial velocity of projectile with mass 0.14 kg
M = mass of target = 2.90 kg
V = velocity of combination
using conservation of momentum
m v = (m + M) V
0.14 v = (0.14 + 2.90) V
V = 0.0461 v
KEi = initial KE = (0.5) m v2
KEf = Final KE = (0.5) (m + M) V2
KEf /KEi = ((m + M)/m) (V/v)2
KEf /KEi = ((0.14 + 2.90)/0.14) (0.0461 v/v)2 = 0.0461
KEf x 100/KEi = 4.61%