D MUKH

(b)OR(c) it is because initially due to F the speed linearly increased .. after that the force decreased but still positive so small increase in velocity then again velocity increases with same slope

if in the middle portion whichever is not completely stiff thats the answer out of B and C i cant see clearly

@ashish , both are completely stiff...

and u told :- then again velocity increases with same slope

how?

the velue of force i.e. acceleration is decreasing but constant...

so slope shud decrease...

but my duobt is about the middle portion ..

ooooh sry...

in middle portion .. dF/dt = -ve..
da/dt = -ve i.e. acceleration is decreasing with time but still it is positive so velocity shud still increase

this is wat i think graf shud be

the answer is

(B)

BECAUSE IN THE LAST CURVE ACCELERATION IS 0
=> VELOCITY IS CONSTANT AND PASSES THROUGH THE ORIGIN

The answer is supposed to be d.
as the slope is initially constant then increases, decreases and is finally again constant