Answer:
b) 20 kJ
Explanation:
Efficiency of carnot engine = (T₁ - T₂ ) / T₁ Where T₁ is temperature of hot source and T₂ is temperature of sink .
T₁ = 270 + 273 = 543K
T₂ = 50 + 273 = 323 K
Putting the given values of temperatures
efficiency = (543 - 323) / 543
= .405
heat input = 50 KJ
efficiency = output work / input heat energy
.405 = output work / 50
output work = 20.25 KJ.
= 20 KJ .
Most of the time, butterflies have bilateral symmetry. This means that there is one line of symmetry. Since butterflies are the same to the left as to the right, this is true.
Hope this helps!
Answer: Three forces act significantly on a freely floating helium-
filled balloon: gravity, air resistance (or drag force), and a
buoyant force.
Explanation:
The air pressure on the bottom of the balloon is slightly higher than the air pressure on the top of the balloon (because of the altitude difference). This difference gives rise to the bouyant force. This force competes with gravity as the two main forces acting on the balloon. Every time your feet hit the ground when you are running, the ground hits your feet with an equal and opposite force. Newton’s third law explains how balloons and rocket engines work. When the neck of an inflated balloon is released, the stretched rubber material pushes against the air in the balloon. The air rushes out of the neck of the balloon.
