One object is traveling northeast with a momentum of 12 kg-m/s, while a second object is traveling southwest on the same path as the first object with a momentum of 4 kg-m/s. When the two objects collide, they stick together. What is the momentum after their collision?(1 point)

Responses

16 kg-m/s southwest
16 kg-m/s southwest

8 kg-m/s southwest
8 kg-m/s southwest

16 kg-m/s northeast
16 kg-m/s northeast

8 kg-m/s northeast

1 answer

To find the momentum after the collision, we need to first determine the momentum of each object in component form, then find the total momentum and its direction.

  1. Object 1:

    • Momentum = \(12\) kg-m/s (northeast)
    • In component form:
      • \(p_{1x} = 12 \cos(45^\circ) = 12 \cdot \frac{\sqrt{2}}{2} = 6\sqrt{2}\) kg-m/s (east)
      • \(p_{1y} = 12 \sin(45^\circ) = 12 \cdot \frac{\sqrt{2}}{2} = 6\sqrt{2}\) kg-m/s (north)
  2. Object 2:

    • Momentum = \(4\) kg-m/s (southwest)
    • In component form:
      • \(p_{2x} = 4 \cos(225^\circ) = 4 \cdot \left(-\frac{\sqrt{2}}{2}\right) = -2\sqrt{2}\) kg-m/s (west)
      • \(p_{2y} = 4 \sin(225^\circ) = 4 \cdot \left(-\frac{\sqrt{2}}{2}\right) = -2\sqrt{2}\) kg-m/s (south)
  3. Total momentum components:

    • Total \(x\)-component of momentum: \[ p_{x,\text{total}} = p_{1x} + p_{2x} = 6\sqrt{2} - 2\sqrt{2} = 4\sqrt{2} \text{ kg-m/s (east)} \]
    • Total \(y\)-component of momentum: \[ p_{y,\text{total}} = p_{1y} + p_{2y} = 6\sqrt{2} - 2\sqrt{2} = 4\sqrt{2} \text{ kg-m/s (north)} \]
  4. Magnitude of total momentum: \[ \text{Magnitude} = \sqrt{(p_{x,\text{total}}^2 + p_{y,\text{total}}^2)} = \sqrt{(4\sqrt{2})^2 + (4\sqrt{2})^2} = \sqrt{32 + 32} = \sqrt{64} = 8 \text{ kg-m/s} \]

  5. Direction of total momentum:

    • This total momentum is in the direction of northeast because both components (east and north) are positive.

Therefore, the total momentum after the collision is \(8 \text{ kg-m/s}\) in the northeast direction.

The final answer is: 8 kg-m/s northeast.