7. An electric train moving at 20km/hrs . Accelerates to a speed of 30km/hrs. in
20 sec, find the distance travelled in meters during the period of
acceleration​

Answer

NB:

- speed, U is measure in m/s

- acceleration, a is measured in m/s²

-time t in seconds , s

Therefore conversation must be made

Speed U = 20km/hrs

=20km÷1hr

But 20km= 20×1000=20000m

1hr= 1×60min×60sec=3600s

U=20000÷3600=5.56m/s

a=30km/hrs

=30km÷1hr

But 30km=30×1000=30000

1hr=3600s

a=30000÷3600=8.33m/s²

From the equation of motion

S=Ut + ½ at².

Where s= distance

S = 5.56m/s × 20s + ½(8.33m/s²)(20s)²

S = 1777.3m