Given:
Acceleration is uniform and acceleration (a) = 10 m/s^2
Now it has been mentioned for the first 2 secs the acceleration is 10m/s^2 .
Hence velocity= acceleration x time
Velocity= 10 x 2 = 20 m/s
Consider s as the distance traveled in the 3rd second.
Now we know s= ut+1/2(at^2)
Where s is the distance measured in m.
u is the initial velocity measured in m/sec
t is the time taken for the object to travel the above distance. This is equal to one second as we need to calculate the distance traveled between 3rd and 2nd second.
t = (3-2)= 1 sec
Substituting the given values in the above formula we get
s = 20 x1 + 1/2 (10 x 1 x 1)
s = 25 m
Thus the distance traveled by the object in the 3rd second is 25 m