- #1

- 4

- 1

- Homework Statement
- A hovering fly is approached by an enraged elephant charging at 2.1 m/s. Assuming that the collision is elastic at what speed does the fly rebound? Note that the projectile(the elephant) is much more massive than the stationary target (the fly)

- Relevant Equations
- 1-D Elastic collisions where v2 = 0:

v'1 = ((m1-m2)/m1+m2)*v1

v'2 = (2m1/(m1+m2))*v1

1 = elephant

2 = fly

So I am trying to find v'2 which is the final velocity of the fly. I have v1 the initial velocity of the elephant 2.1m/s. So I plug it into the equation and have v'2=(2m1/(m1+m2))*2.1m/s. We are not given the masses so I just know m1>m2 but I don't understand how that will help me, or how we can get rid of the masses to solve the equation.

2 = fly

So I am trying to find v'2 which is the final velocity of the fly. I have v1 the initial velocity of the elephant 2.1m/s. So I plug it into the equation and have v'2=(2m1/(m1+m2))*2.1m/s. We are not given the masses so I just know m1>m2 but I don't understand how that will help me, or how we can get rid of the masses to solve the equation.