Everything Science Grade 12

6.4 CHAPTER 6. MOTIONIN TWO DIMENSIONS

pi = pf

pi 1 + pi 2 = pf

m 1 vi 1 + m 2 vi 2 = (m 1 + m 2 )vf

(500)(0) + (500)(2) = (500 + 500)vf

1000 = 1000vf

vf = 1 m· s−^1

Therefore, the final velocity of the resulting mass of cars is 1

m·s−^1 to the left.

Example 12: Colliding balls of clay

QUESTION

Two balls of clay, 200 g each, are thrown towards each other according to

the following diagram.When they collide, they stick together and move off

together. All motion istaking place in the horizontal plane. Determine the

velocity of the clay afterthe collision.

200 g 2

4 m· s−^1

1

200 g

3 m· s−^1

1+2

N

?

SOLUTION

Step 1 : Analyse the problem