Question

I need to know how to do these and the formula too.

Answer 1

a = 4m kgm/s & b. v = 4 m/s

Step-by-step explanation:

a:

A is approaching in the opposite direction of B

So let's take the velocity of A as negative.

Here we'd need to solve this using conservation of momentum.

m1u1 + m2u2 = m1v1 + m2v2

So initial momentum = (m X (-4)) + (m X 8) = -4m + 8m = 4m

b:

After collision sphere A stops, so v = 0 for sphere A

Using the conservation of momentum formula, we get

(m X (-4)) + (m X 8) = (0 X m) + (m X v) [let the final velocity of B be v]

⇒ 4m = vm

⇒ v = 4 m/s