A 1200 kg car is traveling 21.1 m/s. It collides with a stationary car of mass 1500 kg, and the two vehicles lock together. What is the speed of the combined cars immediately after the collision?

A) 7.5 m/s

B) 16.5 m/s

C) 9.4 m/s

D) 11.8 m/s

Answer:

C) 9.4 m/s

Explanation:

[tex]m_1[/tex] = Mass of moving car = 1200 kg

[tex]u_1[/tex] = Initial velocity of moving car = 21.1 m/s

[tex]m_2[/tex] = Mass of stationary car = 1500 kg

[tex]u_2[/tex] = Initial velocity of stationary car = 0

v = Velocity of the combined cars

As the momentum in the system is conserved we have

[tex]m_1u_1+m_2u_2=(m_1+m_2)v\\\Rightarrow v=\dfrac{m_1u_1+m_2u_2}{m_1+m_2}\\\Rightarrow v=\dfrac{1200\times 21.1+1500\times0}{1200+1500}\\\Rightarrow v=9.378\approx 9.4\ \text{m/s}[/tex]

The velocity of the combined mass is 9.4 m/s.

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Memories
by matthew smith

I remember when I met you
the smile on your face,
Seems like a million years ago -
a different time and place

I remember when I kissed you
the warmth inside my heart,
I thought it'd last a lifetime
I swore we'd never part

I thought about the future
I started making plans,
Forever you'd be my woman
forever I'd be your man

We went together places
so that everyone could see,
The women that I want to share
the rest of my life with me

I told you that I loved you
I told you that I cared,
I told you if you were falling
just look back and I'd be there

I know I didn't have all the answers
sometimes I only guessed,
But, through it all I have to say
"I always tried my best"

I wasn't always perfect
I wasn't always right,
I know sometimes I wasn't
even worthy in your sight

I know I took for granted
the love you had to share,
All I ever wanted was
for you to know I cared

Our lives have changed directions
as sometimes lovers do,
Often time and change
and pave a path that's new

Sometimes I often wondered
just what lies ahead,
Sometimes I'd like to turn back time
and take back what I said

We've both gone different places
we've both gone different ways,
I know sometimes I let you down
when trouble came our way

I know sometimes I did things
you didn't comprehend,
But, through the years and all the tears
our memories will never end........