An elephant, which has a mass of 2200 kg., is moving with a velocity of 11.0 m/s across a frozen lake in Africa when itbegins to slide across the ice. The sliding elephant then collides with a massive 4000.0 kg ball of putty which was left behindwhen a local pottery business went kaput. After the collision the elephant sticks to the putty and both slide across the icetogether. What will be the velocity of the elephant-putty combination?

the velocity of the elephant-putty combination will be v final=3.548 m/s

Explanation:

If we neglect friction of the ice then for the system formed by the elephant and the putty, the momentum is conserved. From Newton's second law:

F = d (mv) / dt = 0 → d (mv) = 0 → mv = constant

where m = mass, v = velocity, F=force, t=time

Also we assume perfectly inelastic collision between the elephant and the putty → since the elephant sticks to the putty and slide together

therefore denoting "el" and "pu" as elephant and putty respectively:

m el * v el + m pu * v pu = (m el + m pu) * v final

since the putty is initially at rest v pu=0, then

v final = m el / (m el + m pu) * v el = 2200 kg / (2200 kg+4000kg) * 11 m/s = 3.548 m/s

v final = 3.548 m/s