Question

$(3000kg)v_{fx}=(2000kg)(5.0m/s)+(1000kg)(-4.0m/s)$

a. Write a realistic problem for which this is the correct equation(s).

b. Finish the solution of the problem, including a pictorial representation.

Short answer

a) Car of mass 2000 kg is moving towards right with speed 5.0 m/s, then it collides with 1000 kg car that moves towards left with the speed of 4.0 m/s and then they moves together. Find the speed of combination after collision and its direction.

b) Speed of the combination is 2.0 m/s towards Right.

Step-by-step solution

Step 1. Given equation is (3000 kg)vfx=(2000 kg)(5.0 m/s)+(1000 kg)(-4.0 m/s)  

We need to find out a realistic problem for which this is the correct equation and have to find out the solution including pictorial representation.

Step 2. Expressing the realistic problem of the given equation.  

There are two masses that become together after the collision.

So the equation will be :

"Car of mass 2000 kg is moving towards right with speed 5.0 m/s, then it collides with 1000 kg car that moves towards left with the speed of 4.0 m/s and then they moves together. Find the speed of combination after collision and its direction"

Step 3. Using the law of conservation of momentum to find the speed of the combination and its direction.

$$\begin{gathered} (3000kg)v_{f.x}=(2000kg)(5m/s)+(1000kg)(-4m/s) \\ {v}_{f.x}=\frac{(10000-4000)kgm/s}{3000kg} \\ {v}_{f.x}=\frac{\left(6000\right)kgm/s}{3000kg}=2.0m/s \end{gathered}$$

(Positive value means towards right)

Pictorial Representation,