# Please solve - simultaneous equation

#### GAVREED2

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
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?

Last edited:
• GAVREED2

#### GAVREED2

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
I have made an edit above

You need to solve

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

Now (1)-(2)=?

• GAVREED2