= Heat released to cold reservoir
= Heat released to hot reservoir
= maximum amount of work
= temperature of cold reservoir
= temperature of hot reservoir
we know that
eq-1
maximum work is given as
= -
using eq-1
= 
-
Given that,
Initial velocity , Vi = 0
Final velocity , Vf = 40 m/s
Acceleration due to gravity , a = 9.81 m/s²
Distance can be calculated as,
2as = Vf² - Vi²
2 * 9.81 *s = 40² - 0²
s = 81.55 m
For half height, that is, s = 40.77m
Vf= ??
2as = Vf² - Vi²
2 * 9.81 * 40.77 = Vf² - 0²
Vf² = 800
Vf = 28.28 m/s
Therefore, speed of roller coaster when height is half of its starting point will be 28 m/s.
Answer:
Sea-floor spreading occurs in the oceanic ridges. In there, volcanic activity, together with the gradual movement of the bottom, form new oceanic crust. This allows a better understanding of the continental drift explained by the theory of plate tectonics.
The greatest evidence for Sea-floor spreading is the oceanic trenches, the oceanic ridges, the magma protruding to the surface and the new seafloor.
In previous theories, continents were assumed to be transported across the sea. Harry Hess, in the 1960s, proposed the idea that the seabed itself moves as it expands from a central point. The theory is now accepted, and the phenomenon is thought to be caused by convection currents in the upper layer of the mantle.
Answer:
False
Explanation:
All the lanthanides are not radioactive in nature. Just one of the lanthanides are radioactive.
- The lanthanides belong to the f-block on the periodic table
- Only Promethium in this group are radioactive in nature.
- Other elements in the lanthanide series might have radioactive isotopes.
Answer:
Explanation:
For resistance of a wire , the formula is as follows
R = ρ L / S
where ρ is specific resistance , L is length and S is cross sectional area
Given L = 14 000 m ,
S = 4.8 x 10⁻⁴ m²
specific resistance of aluminum = 2.8 x 10⁻⁸ ohm-meter
Putting the values in the formula
R = 2.8 x 10⁻⁸ x 14 x 10³ / (4.8 x 10⁻⁴ )
R = 0.8167 ohm .
= .82 ohm .
