contestada

A small 0.1 kg cart is moving at 1.20 m/s on a frictionless track when it collided with a larger 1.00 kg cart at rest. After the collision, the same cart recoils at 0.850 m/s (backwards). What is the speed of the larger cart after the collision

Respuesta :

Answer: 0.205 m/s

Explanation:

According the conservation of momentum law, the total momentum before the collision ([tex]p_{i}[/tex]) is equal to the total momentum after the collision ([tex]p_{f}[/tex]):

[tex]p_{i}=p_{f}[/tex] (1)

Being:

[tex]p_{i}=m_{1}V_{1}+m_{2}V_{2}[/tex] (2)

[tex]p_{f}=m_{1}U_{1}+m_{2}U_{2}[/tex] (3)

Where:

[tex]m_{1}=0.1 kg[/tex] is the mass of the first cart

[tex]V_{1}=1.20 m/s[/tex] is the initial velocity of the first cart

[tex]m_{2}=1 kg[/tex] is the mass of the second cart

[tex]V_{2}=0 m/s[/tex] is the initial velocity of the second cart

[tex]U_{1}=-0.85 m/s[/tex] is the final velocity of the first cart

[tex]U_{2}[/tex] is the final velocity of the second cart

Substituting (2) and (3) in (1):

[tex]m_{1}V_{1}+m_{2}V_{2}=m_{1}U_{1}+m_{2}U_{2}[/tex] (4)

Isolating [tex]U_{2}[/tex]:

[tex]U_{2}=\frac{m_{1}(V_{1}-U_{1})}{m_{2}}[/tex] (5)

[tex]U_{2}=\frac{0.1 kg(1.20 m/s-(-0.85 m/s))}{1 kg}[/tex] (6)

Finally:

[tex]U_{2}=0.205 m/s[/tex] This is the speed of the second cart after the collision