We have by the first law of thermodynamics tha energy is preserved, hence we cannot have over 840kJ per cycle. We have by the laws of thermodynamics (the 2nd one in specific) that the entropy of a system cannot increase. We cannot have an output of 840 kJ per cycle from a heat engine because then that would mean that the entropy would stay the same, while any heat engine increases it. Hence, any value
is acceptable.
Answer:
Explanation:
Given that
Force constant k=8.6N/m
Weight =64g=64/1000=0.064kg
Extension is 45mm=45/1000= 0.045m
It will have it highest spend when the Potential energy is zero
Therefore energy in spring =change in kinetic energy
Ux=∆K.e
½ke² = ½mVf² — ½mVi²
Initial velocity is 0, Vi=0m/s
½ke² = ½mVf²
½ ×8.6 × 0.045² = ½ ×0.064 ×Vf²
0.0087075 = 0.032 Vf²
Then, Vf² = 0.0087075/0.032
Vf² = 0.2721
Vf=√0.2721
Vf= 0.522m/s
The time it will have this maximum velocity?
Using equation of motion
Vf= Vi + gr
0.522= 0+9.81t
t=0.522/9.81
t= 0.0532sec
t= 53.2 milliseconds
Best answer is D) groundwater
Caves generally form by the slow (very very slow) dissolution of soluble rock, such as limestone, which is dissolved by the acid in groundwater. Stalagmites and stalactites are evidence of this very slow dissolution process.
