Answer:
+16 J
Explanation:
We can solve the problem by using the 1st law of thermodynamics:

where
is the change of the internal energy of the system
Q is the heat (positive if supplied to the system, negative if dissipated by the system)
W is the work done (positive if done by the system, negative if done by the surroundings on the system)
In this case we have:
Q = -12 J is the heat dissipated by the system
W = -28 J is the work done ON the system
Substituting into the equation, we find the change in internal energy of the system:

Answer:
4.123 * 10∧4 kg
Explanation:
mass of car M' = 3.34 * 10∧4 kg
energy loss E = 19/100 K
from law of conservation of momentum ,
M' V' = ( M' + M'' ) v
V = M' V' / ( M' + M'' )
Initial kinetic energy is K' = (M' V')² / 2
final kinetic energy K" = 81 K' /100
= (M' V')² 81 / (200) = ( M' + M'' ) v²/ 2
therefore , M' / ( M' + M" ) = 0.81
mass of caboose is , M" = 1.234 M' - M'
M" = .234 M'
= 0,234 ( 3.34 * 10∧4 kg)
= 4.123 * 10∧4 kg
Yes, I think that the universe is way to large for there not to be other life forms out there.