A particle slides along a straight wire so that a $=-$k$/$v where a is the acceleration, v is the velocity,

$0$and k $=20$ m $/$s $.$ The particle stars at x $=0,$ t $=0,$ with a speed v $=10$ m$/$s$\mathrm{.}23$

$2.$ When the particle is at

x $=4$ m$,$ the speed v is

most nearly

A$.2\mathrm{.}49$ m$/$s

B$.3\mathrm{.}46$ m$/$s

C$.5\mathrm{.}29$ m$/$s

D$.6\mathrm{.}93$ m$/$s

E$.7\mathrm{.}50$ m$/$s

F$.8\mathrm{.}62$ m$/$s

G$.8\mathrm{.}88$ m$/$s

H$.9\mathrm{.}13$ m$/$s

I. $9\mathrm{.}81$ m$/$s

J$.10\mathrm{.}00$ m$/$s

$3.$ For the same particle,

when t $=1\mathrm{.}3$ s$,$ the

speed v is most nearly

A$.2\mathrm{.}49$ m$/$s

B$.3\mathrm{.}46$ m$/$s

C$.5\mathrm{.}29$ m$/$s

D$.6\mathrm{.}93$ m$/$s

E$.7\mathrm{.}50$ m$/$s

F$.8\mathrm{.}62$ m$/$s

G$.8\mathrm{.}88$ m$/$s

H$.9\mathrm{.}13$ m$/$s

I. $9\mathrm{.}81$ m$/$s

J$.10\mathrm{.}00$ m$/$s