Question

A 100-kg moving at 15 m/s collides with a 50-kg cart at rest causing both cars to move together in the same direction. If momentum is conserved, at what speed are the two carts now moving?

Answer 1

Answer:

30m/s

Explanation:

100 / 50 = 2 * 15 = 30m/s

Answer 2

Answer:

$\boxed{\text{10 m/s}}$

Explanation:

Data:

Cart 1: m₁ = 100 kg; v  =15 m/s

Cart 2: m₂ =  50 kg; v₂ = ?

Calculations:

I assume that the two carts are going at the same speed v₂ after the collision.

$\begin{array}{rcl}\text{Momentum before collision} & = & \text{Momentum after collision} \\\text{100 kg} \times\text{15 m/s} & = &\text{100 kg} \times v_{2} + \text{50 kg} \times v_{2}\\\text{1500 m/s} & = & 100 v_{2} +50 v_{2}\\\text{1500 m/s} & = & 150 v_{2}\\v_{2}& =&\textbf{10 m/s}\\\end{array}\\\\\text{The two carts are now moving at a speed of }\boxed{\textbf{10 m/s}}$