Question

A 12000kg railroad car is travelling at 2m/s when it strikes another 10000kg railroad car that is at rest .if the cars lock together what is the final speed of the two railroad cars​

Answer 1

Answer:

This is a perfectly inelastic collision and we can use conservation of momentum.

Basically, the monentum before must be the same as the momentum after the impact (momentum being the product of mass times velocity).

Answer 2

$\huge {\orange {\bf {\underline {\underline {AnSwer}}}:-}}$

Final velocity of the two railroad cars is 1.1 m/s

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Explaination :-

➠ Given :-

➝ Mass of the moving railroad=12000kg

➝ Initially, it's velocity= 2 m/s

➝ Mass of railroad at rest= 10000 kg

➝ They strikes and locked up

➠ To find :-

➝ Final speed of the system of railroad cars

➠ Solution :-

We have,

⇒$\sf m_1$ = 12000 kg

⇒$\sf m_2$ = 10000 kg

⇒$\sf u_1$ = 2 m/s

⇒$\sf u_2$ = 0 m/s (at rest)

Final masses will be their sum

So, By using formula of Conservation of momentum

$\longrightarrow \sf m_1u_1 + m_2u_2 =( m_1 + m_2)v$

$\longrightarrow \sf(12000)(2) + (10000)(0) = (12000 + 10000)v$

$\longrightarrow \sf 24000 + 0 = 22000v$

$\longrightarrow \sf v = \cancel\frac{24000}{22000}$

$\longrightarrow \sf v = \frac{12}{11} {ms}^{ - 1}$

$\longrightarrow \boxed {\bf v = 1.1 {ms}^{ - 1} } \: \: \: \: ( \sf approx)$

Thus, Final velocity of the two railroad cars is 1.1 m/s