Answer:
1.53 m/s
Explanation:
Given:
Mass of the car (M) = 1300 kg
Mass of the coal (m) = 400 kg
Initial velocity of the car (U) = 2 m/s
Initial velocity of the coal (u) = 0 m/s (Since it is dropped)
When the coal is dropped into the car, then they move with same final velocity.
Let the final velocity be 'v' m/s.
For a closed system, the law of conservation of momentum holds true.
So, initial momentum is equal to final momentum of the car-coal system.
Initial momentum of the car = [tex]MU=1300\times 2=2600\ Ns[/tex]
Initial momentum of the coal = [tex]mu=0\ Ns[/tex]
Total initial momentum is the sum of the above two momentums.
So, total initial momentum = 2600 + 0 = 2600 Ns
Now, final momentum is given as the product of combined mass and final velocity. So,
Final momentum of the system = [tex](M+m)v=(1300+400)v=1700v[/tex]
Now, from law of conservation of momentum,
Initial momentum = Final momentum
[tex]2600=1700v\\\\v=\frac{2600}{1700}\\\\v=1.53\ m/s[/tex]
Therefore, the final velocity of either of the two masses is same is equal to 1.53 m/s.