Answers

2014-12-13T07:15:45+05:30
I think it's 40j because
ek=1/2mv²
i.e 1/2*5*4²
=5*2*4=40

0
srry,i didnt noticed that 10
no actually the answer is 400 J
if u can then pls try to do it .....
may be,multiply that present Ek by the time taken(10)
2014-12-13T12:02:01+05:30
Let velocity after 10s be v
                           t=10 s  , m =5kg  a =4m/s²
               We have v = at = 4*10=40m/s
                KE= mv²/2= 5*40²/2=4000 joules
0
mark as the best
but the ans is 400J