Question

A car starting from rest on a straight road first acceleration with $6$ m/s then suddenly decelerates with $3m/s$ till it stops if total time of journey is $10$ seconds, Then the maximum speed and distance acquired by the car is:

Answer 1

If car is starting from rest then its initial velocity is $0$

so $u=0$

$a=2$

$t=10$

2) Using relation $v=u+at$

$v=0+2\times 10$

$v=20m/s$

1) Using relation

$v^2-u^2=2as$

$(20{)}^2-0=2\times 2\times s$

$s=400/4$

$s=100m$