Find out distance travelled by the block in 10 sec. for a given situation

Explanation

First find out it what instant velocity of block becomes zero.
v=u+at
given: u=10 m/s, a`=-2m//s^2`
`implies0=10-2t`
`impliest=5` sec
So we calculate distance for two time intervals.
for first 5 sec
`S_1=ut-1/2at^2`
`impliesS_1=(10)(5)-1/2(2)(5)^2=25m`
for Next 5 sec (blockis travelling towards the starting point) `S_2=ut+1/2at^2`
u=0
`S^2=1/2xx2xx25=25m`
`S=S_1+S_2=50m`