According to the law of reflection, when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.
So in the above situation, if the incident ray makes an angle of 65° with respect to the normal to the mirror's surface, the angle of reflected ray will also be equal to 65 degrees. The attached image will explain this better.
So the answer is,
c. 65 degrees
Answer:
115 m/s, 414 km/hr
Explanation:
There are two forces acting on a skydiver: gravity and air resistance (drag). At terminal velocity, the two forces are equal and opposite.
∑F = ma
D − mg = 0
D = mg
Drag force is defined as:
D = ½ ρ v² C A
where ρ is the fluid density,
v is the velocity,
C is the drag coefficient,
and A is the cross sectional surface area.
Substituting and solving for v:
½ ρ v² C A = mg
v² = 2mg / (ρCA)
v = √(2mg / (ρCA))
We're given values for m and A, and we know the value of g. We need to look up ρ and C.
Density of air depends on pressure and temperature (which vary with elevation), but we can estimate ρ ≈ 1.21 kg/m³.
For a skydiver falling headfirst, C ≈ 0.7.
Substituting all values:
v = √(2 × 80.0 kg × 9.8 m/s² / (1.21 kg/m³ × 0.7 × 0.140 m²))
v = 115 m/s
v = 115 m/s × (1 km / 1000 m) × (3600 s / hr)
v = 414 km/hr
<h3><u>Answer</u> :</h3>
<u>Focal length of convex lens is taken positive.</u>
Answer:
Increase in surface area leads to more chances for connections between neurons hence more possible learning
Explanation:
The brain appears wrinkled due to the presence of gyri and sulci. Sulci are the grooves in the brain while gyri are the folds. The two major functions of gyri and sulci are to lead to formation of brain divisions and increase the surface area of cerebral cortex. The formation of brain divisions is done by creating boundaries between the brain lobes thereby leading to division of the brain into two hemispheres. Moreover, by increasing the surface area of the brain, the cortex processes more information since more neurons are formed.
