Respuesta :
Answer:
The correct option is;
B. 4.2 m/s
Explanation:
The mass of the toy train car in motion = 50 kg
The velocity of the toy train car = 5 m/s
The mass of the toy vertically dropped into the car = 10 kg
Therefore, we have from the conservation of linear momentum;
The initial momentum of the train car = The total momentum of the train car and toy
The initial momentum of the train car is given as follows;
Momentum = Mass × Velocity
Initial momentum of the train car = Mass of the train car × Velocity of the train car
Initial momentum of the train car = 50 kg × 5 m/s = 250 kg·m/s
The total momentum of the train car and toy = (Mass of the toy + Mass of the train car) × Final speed immediately after the toy is dropped
The total momentum of the train car and toy = (10 kg + 50 kg) × v = 60 kg × v
Given that the initial momentum of the train car = The total momentum of the train car and toy
We have;
250 kg·m/s = 60 kg × v
v = 250 kg·m/s/(60 kg) = 4.1[tex]\bar 6[/tex] m/s
v = 4.1[tex]\bar 6[/tex] m/s ≈ 4.2 m/s
∴ The speed immediately after the toy is dropped, v ≈ 4.2 m/s.
