Physics Pastpaper M/J 10 help and a A book

[arabiannight975]

Guys Physics M/J 2010, P21 ....
question 2 B ii

HOw is the speed 2.8 ? i jsut cant get it !:S

and yes, abother question, iu have the book called, AS revision by letts and lonsdale,
like if I study the whole book, sis that enough?

 

[diwash]

First of all draw a tangent to the curve at time time 0.4 s
(A line just touching the curve at 0.4 s)
then u need to calculate the gradient (slope) of the tangent.

the gradient of s-t graph at tme 0.4 s is velocity at that instant. I think now u can get the answer...

 

[arabiannight975]

I tired doing so, the answer comes as 3.8 in any case, i am wondering if its a printing mistake in the marking scheme, cuz that happened quite often in the IG's physics!

or maybe its just that i am DUMB as hell lol!