Question

A train car with a mass of 10 kg and speed of 10 m/s is traveling to the right. Another train car with an unknown mass is stationary. After the collision, the 10 kg train car is now moving at 5 m/s and the second train is movingat 25 m/s.

Answer 1

mass of car 2 is after collision is 2 kg

Step-by-step explanation:

Since the cars were not stuck after collision, the collision is elastic. By applying the law of conservation of momentum,

m1u1 + m2u2 = m1v1 + m2v2

where

m1 is the mass of train car 1

u1 is the initial velocity of train car 1

m2 is the mass of train car 1

u2 is the initial velocity of train car 2

v1 is the final velocity of train car 1

v2 is the final velocity of train car 2

From the information given,

m1 = 10

u1 = 10

m2 = ?

u1 = 0

v1 = 5

v2 = 25

By substituting these values into the formula, we have

10 x 10 + 0 x m2 = 10 x 5 + m2 x 25

100 - 0 = 50 + 25m2

100 = 50 + 25m2

25m2 = 100 - 50 = 50

m2 = 2kg