Question

If a body starting from the rest travels with a uniform acceleration of 10m/s² for first 10 seconds and with uniform acceleration 5m/s² for next 20 seconds, then average acceleration of the body for 30s is

Answer 1

a1=10
a2=5
average a=a1+a2/2
10+5/2
7.5 m/s²

Answer 2

7.5 is the right answer because science has proved it