Question

1. a railroad car slams into another railroad car and couples together. what is the combined speed of the railroad cars after the collision?m = 4000 kgv = 2 m/sbeforem = 6000 kgv = 0 m/safterv = ?9. two blocks moving in opposite directions collide and stick together after the collision. what is their combined speed after the collision?8 $\frac{m}{sec}$1kg1 $\frac{m}{sec}$2kg10. an explosion causes the cars to move apart from each other. according to the diagram below, what is the speed of each of the cars as they move away from each other?before explosionafter explosionp total = 0p to the left = 20p to the right = 20p total = 011. a 3000-kg truck moving rightward with a speed of 5 km/hr collides head-on with a 1000-kg car moving leftward with a speed of 10 km/hr. the two vehicles stick together and move with the same velocity after the collision. determine the post-collision speed of the car and truck.

Explanation:

Step1: Define conservation of momentum

For perfectly inelastic collisions (objects stick together), total initial momentum equals total final momentum: $m_1v_1 + m_2v_2 = (m_1+m_2)v_f$

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Problem 8

Step1: Plug in given values

$m_1=4000\ \text{kg}, v_1=2\ \text{m/s}, m_2=6000\ \text{kg}, v_2=0$
$\text{Initial momentum} = (4000 \times 2) + (6000 \times 0) = 8000\ \text{kg·m/s}$

Step2: Solve for final velocity

$8000 = (4000+6000)v_f$
$v_f = \frac{8000}{10000}$

Answer:

(Problem 8):
$0.8\ \text{m/s}$

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Problem 9

Step1: Assign direction signs (right = +)

$m_1=1\ \text{kg}, v_1=8\ \text{m/s}, m_2=2\ \text{kg}, v_2=-1\ \text{m/s}$
$\text{Initial momentum} = (1 \times 8) + (2 \times -1) = 8-2=6\ \text{kg·m/s}$

Step2: Solve for final velocity

$6 = (1+2)v_f$
$v_f = \frac{6}{3}$