Question number two. please help.

Momentum = (mass) x (velocity) in the direction of the velocity.

Change of momentum = "impulse" = (force) x (time)



2-a).  Momentum before the hit = (0.14) x (40) = 5.6 N-m/s toward the East.

Momentum after the hit = (0.14) x (46) = 6.44 N-m/s toward the West.

Change in momentum = (5.6) + (6.44) = 12.04 N-m/s .
(The hit soaked up all the momentum pointing east, and then provided
momentum toward the west. So the total change in momentum is the
sum of before- and after-.)
(The east momentum changed from 5.6 to zero, and the west momentum
changed from zero to 6.44.  So the total change is the sum of before-and after-.)
(If you call east the positive direction, then the momentum changed
from +5.6 to -6.44, and the difference between those is 12.04 .)

2-b).  12.04 N-m/s = (Force) x (0.012 second)

Force = 12.04 / 0.012 = 1,003 and 1/3 Newtons

B) as the temperature increases, the kinetic energy of the particles increases.|-/

P