Collision Problem. Need help!

4 Km/hr

Explanation:

Data obtained from the question include the following:

Mass of ball (Mb) = 15 Kg

Velocity of ball (Vb) = 20 Km/hr

Mass skater (Ms) = 60 Kg

Velocity of skater (Vs) = 0 Km/hr

Velocity after collision (V) =..?

Thus, we can obtain the velocity after collision as follow:

MbVb + MsVs = V(Mb + Ms)

(15 x 20) + (60 x 0) = V (15 + 60)

300 + 0 = 75V

300 = 75V

Divide both side by 75

V = 300/75

V = 4 Km/hr.

Therefore, the velocity after the collision is 4 Km/hr.

explanation:

as the height from which the ruler was dropped increased, the speed of the ruler at ryan's hand increased.