Answer:
-5.8 m/s
Explanation:
Given:-
- The mass of Big Bubba, mb = 125 kg
- The mass of Lil' Pete, mp = 80 kg
- The initial velocity of Big Bubba, vb = 7 m/s
- The initial velocity of Lil Pete , vp = -10 m/s
- The velocity after impact of Lil' Pete, vp' = + 10 m/s
- The velocity after impact of Big Bubba = vb'
Find:-
what is Big Bubba's velocity after the collision?
Solution:-
- We will consider the two football players as particles of mass mb and mp with their respective velocities vb and vp heading towards each other.
- The masses collide and both reverse in direction with velocities vb' and vp'.
- The system of the two masses have no external forces acting on it; hence, the system is isolated from any fictitious forces.
- For above conditions we can apply the principle of conservation of linear momentum. The linear momentum of two football players before ( Pi ) and after the impact ( Pf ) remain constant. The conservation is:
Pi = Pf
mb*vb + mp*vp = mb*vb' + mp*vp'
mb*vb + mp*( vp - vp' ) = mb*vb'
- Develop an expression for Big Bubba's velocity after impact vb':
vb' = vb + mp/mb*( vp - vp' )
- Plug in the values and evaluate:
vb' = 7 + 80/125*( -10 - 10 )
vb' = 7 - 80*20 / 125
vb' = -5.8 m/s
Answer: The velocity of Big Bubba after impact is vb' = -5.8 m/s
