Answer:
18.9 m.
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Final velocity (v) = 70 km/h
Height (h) =?
Next, we shall convert 70 km/h to m/s. This can be obtained as follow:
3.6 km/h = 1 m/s
Therefore,
70 km/h = 70 km/h × 1 m/s / 3.6 km/h
70 km/h = 19.44 m/s
Finally, we shall determine the height. This can be obtained as follow:
Initial velocity (u) = 0 m/s
Final velocity (v) = 19.44 m/s
Acceleration due to gravity (g) = 10 m/s²
Height (h) =?
v² = u² + 2gh
19.44² = 0² + (2 × 10 × h)
377.9136 = 0 + 20h
377.9136 = 20h
Divide both side by 20
h = 377.9136 / 20
h = 18.9 m
Thus, the car will fall from a height of 18.9 m
Answer:
Explanation:
This problem relates to interference of light in thin films .
The condition of bright fringe in thin films which is sandwitched by two layers of medium having lesser refractive index is as follows.
2nt = (2n+1) λ / 2 , n is refractive index of thin layer , t is its thickness , λ is wavelength of light .
2 x 1.5 t = λ / 2 , if n = 0 for minimum thickness.
2 x 1.5 t = 600 / 2 nm
t = 100 nm .
Input heat, Qin = 4 x 10⁵ J
Output heat, Qout = 3.5 x 10⁵ J
From the first Law of thermodynamics, obtain useful work performed as
W = Qin - Qout
= 0.5 x 10⁵ J
By definition, the efficiency is
η = W/Qin
= 100*(0.5 x 10⁵/4 x 10⁵)
= 12.5%
Answer: The efficiency is 12.5%
