Two coupled boxcars are rolling along at 4.0m/swhen they collide with and couple to a third, stationary boxcar.

what is the final speed of the three coupled boxcars?

what fraction of the cars' initial kinetic energy is transformed into thermal energy?

The percentage of kinetic energy transformed into thermal energy is 33.18%.

Explanation:

Given that,

Initial speed of the two car = 4.0 m/s

Let the mass of the box cars be m.

(a). we need to calculate the final speed of the three coupled boxcars

Using conservation of energy

Put the value into the formula

The final speed of the three cars is 2.67 m/s.

(b). We need to calculate the initial kinetic energy

Using formula of kinetic energy

Put the value into the formula

We need to calculate the final kinetic energy

Using formula of kinetic energy

We need to calculate the loss of kinetic energy

We need to calculate the fraction of the cars' initial kinetic energy is transformed into thermal energy

We need to calculate the percentage of kinetic energy transformed into thermal energy

Hence, The percentage of kinetic energy transformed into thermal energy is 33.18%.

d. air pressure decreases as altitude increases.