1. ## Simultaneous word problem - please solve

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

2. Originally Posted by 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
Well you can use simultaneous equations, but first here's an easier way.

The object accelerated 40 m/s in 10 seconds. This means a = 4 m/s^2. Thus at time t=0 the velocity was 30 - (4)(6) = 6 m/s. And the velocity at t = 20 is 70 + (4)(4) = 86 m/s.

If you would rather use simultaneous equations, try

30 = u + a(6)
70 = u + a(16)

3. thanks so much that makes more sense. Just wondering how i would form a simultaneous equation for part c???

4. Originally Posted by GAVREED2
thanks so much that makes more sense. Just wondering how i would form a simultaneous equation for part c???
No need for simultaneous equation for part (c). You have u and a, that is,

V = 6 + 4t

You can plug in t = 20 to get the answer.