Question $12$

$1$ pts

Two trolleys run on a straight and level track. Trolley A has a mass of $3$ kg and a steady speed of $4\frac{m}{s}$ to the right. Trolley $B$ has a mass of $2$ kg and a steady speed of $9\frac{m}{s}$ to the left. After the collision, trolley A has a steady speed of $3\frac{m}{s}$ to the left. What is the steady velocity of trolley $B$ after the collision?

$q,$

$+3\mathrm{.}0$ m$/$s

$+13\mathrm{.}5\frac{m}{s}$

$+7\mathrm{.}5$ m$/$s

$+1\mathrm{.}5$ m$/$s

$+2\mathrm{.}4\frac{m}{s}$