In order to compute the final velocity of the trains, we may apply the principle of conservation of momentum which is:
initial momentum = final momentum
m₁v₁ = m₂v₂
The final mass of the trains will be:
10,000 + 10,000 = 20,000 kg
Substituting the values into the equation:
10,000 * 3 = 20,000 * v
v = 1.5 m/s
The final velocity of the trains will be 1.5 m/s
Answer:
The importance of international bureau of weights and measures are;
1. to bring unification of measurement system.
2. to establish and preserve fundamental international prototypes.
3. to verify national standards, etc.
3.4814815 (or 3 13/27) m/s
speed = distance/time
3.4814815 (or 3 13/27) = 94/27
(1.9 yr) x (365.24 day/yr) x (86,400 sec/day) x (10⁹ nsec/sec)
= (1.9 x 365.24 x 86,400 x 10⁹) nanosec
= 6.00 x 10¹⁶ nanoseconds
The kinetic energy is given by:

We know the mass and the maximum speed, plugging their values in the expression above we have:

Therefore, the answer is d.