Question

A car of mass 1,484 is traveling south at 39 km/hr when it suddenly turns east and speeds up to 54 km/hr. What is the magnitude of change in car's momentum?

Answer 1

Given that mass of car = 1484 kg (Units are missing, SI units used if different let me know)

Vi = Initial velocity of car = 39 km/hr towards south = 39*5/18 = (-10.83 j) m/s

Vf = final velocity of car = 54 km/hr towards east = 54*5/18 = (15 i) m/s

Now change in car's momentum is given by:

dP = Pf - Pi

dP = m*Vf - m*Vi

dP = 1484*15 i - 1484*(-10.83 j)

dP = 1484*15 i + 1484*10.83 j

dP = 22260 i + 16071.72 j

Now magnitude of change in momentum will be:

|dP| = sqrt (22260^2 + 16071.72^2)

|dP| = 27455.56 kg.m/sec

Let me know if you've any query.