Please solve - simultaneous equation

May 2010
64
0
Palmy
This one has had me stumped for a few days now. Hope someone can help shed some light on this question.

1) For a body travelling with constant acceleration of a meters/second^2 its velocity Vm/sec after t seconds is given by V=u+at where u is its initial velocity.

After six seconds the body had a velocity of 30 metres per second. 10 seconds later its velocity V was 70m/sec.

Form a pair of simultaneous equations and solve them to find:
a) the acceleration
b) the intial velocity
c) the velocity after 20 seconds
 

pickslides

MHF Helper
Sep 2008
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Melbourne
its velocity Vm/sec after t seconds is given by V=u+at where u is its initial velocity.

Into this equation substitute in the points \(\displaystyle (t,V)=(6,30)\) and \(\displaystyle (t,V)=(16,70)\) to find \(\displaystyle u\) and \(\displaystyle a\)

Do you follow?
 
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May 2010
64
0
Palmy
So: 30=u+6a
70=30+10a

Does part c) after 20 seconds substitute to
30=u+6a
70=30+20a


Into this equation substitute in the points \(\displaystyle (t,V)=(6,30)\) and \(\displaystyle (t,V)=(10,70)\) to find \(\displaystyle u\) and \(\displaystyle a\)

Do you follow?
 

pickslides

MHF Helper
Sep 2008
5,237
1,625
Melbourne
I have made an edit above

You need to solve

\(\displaystyle 70=u+16a\) ...(1)
\(\displaystyle 30=u+6a\) ...(2)

Now (1)-(2)=?
 
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