$($problems $10-11)$ A $4\mathrm{.}0$ kg block slides along a horizontal, frictionless surface at $10\mathrm{.}0$ m$/$s$.$ It collides

with a stationary $6\mathrm{.}0$ kg block and the two stick together.

$10.$ Find the speed of the blocks after the collision.

a$)8$ m$/$s

b$)7$ m$/$s

c$)6$ m$/$s

d$)5$ m$/$s

e$)4$ m$/$s

$11.$ Find the amount of kinetic energy lost during the collision.

a$)120$ J

b$)130$ J

c$)140$ J

d$)150$ J

e$)160$ J