KEAM 2017 Physics and Chemistry Paper

According to question,
Object P starts at t=0 and
acceleration of P=40km∕h2
The time taken by object P to cover 20km will be,
s=u+‌

1

2

at2
Where, u=0,s=‌

1

2

at2
t=√‌

2s

a

Here, a=40km∕h2
and s=20km
t=√‌

2×20

40

=1 hour
Time taken by Q will be ‌

1

2

hour, because he started after 30 min.
The acceleration in Q,
a=‌

2s

t2

=‌

2×20

(‌ 1 2 )2

=2×4×20
=160km∕h2