Answer:
We show added energy to a system as +Q or -W
Explanation:
The first law of thermodynamics states that, in an isolated system, energy can neither be created nor be destroyed;
Energy is added to the internal energy of a system as either work energy or heat energy as follows;
ΔU = Q - W
Therefore, when energy is added as heat energy to a system, we show the energy as positive Q (+Q), when energy is added to the system in the form of work, we show the energy as minus W (-W).
Potential energy decreases and kinetic energy increases.
Potential energy is related to the height, since the wagon is going downhill, height decreases and potential energy decreases.
Kinetic energy is related to the speed, since the wagon is speeding up, kinetic energy increases.
are you sure it's Thaivan or Taiwan. If it's Taiwan than it's Taipei.
Hope this help :))
Answer:
6.38 x 10^4 J
Explanation:
d = 0.33 cm = 0.33 x 10^-2 m, Area = 87 x 36 cm^2 = 0.87 x 0.36 m^2
ΔT = 14 degree C, t = 1 min = 60 second
K = 0.8 W / m K
Heat = K A ΔT t / d
H = 0.8 x 0.87 x 0.36 x 14 x 60 / (0.33 x 10^-2)
H = 6.38 x 10^4 J
naturally occurring radioactive elements have been around since the Earth's formation
