5 seconds is a poor time to ask about, because the speed abruptly changes at exactly 5 seconds.
Up until that time, the speed has been 1 m/s. And then, at exactly 5 seconds, it becomes zero.
_________
It's also a poor question because speed is calculated from the distance covered, but the graph shows displacement, not distance. You can't really tell the distance covered from a displacement graph.
For example, if an object happens to be moving in a circle around the place where it started, then the total distance covered keeps increasing, but its displacement is constant.
Answer: 115m. Displacement can be taken from the distance between the initial point and the final point. In this case,the displacement is 115m.
Answer:
E = 1/2 M V^2 = 1/2 P V since P = M V
E2 / E1 = P2 V2 / (P1 V1)
P2 / P1 = E2 V1 / (E1 V2) = V2^2 V1 / (V1^2 V2) = V2 / V1
E2 / E1 = V2^2 / V1^2
V2 / V1 = (E2 / E1)^1/2
V2 / V1 = (.9)1/2 = .95
The linear momentum would have to decrease by 5%
