Answer: A
Explanation:
From the figure given as attachments, the error pointing upward signifies the incident ray while the one point downwards signifies the reflected ray.
One of the laws of reflection is stated that the angle of incidence is equal to the angle of reflection.
Since the two arrows are parallel to each other, then the mirror must be perpendicular to the two arrows. That is, the incident ray and the reflected ray must be perpendicular to the mirror.
Option A is the correct answer.
Answer: Option A: 22.5 m
Explanation:
A stone is dropped from a tower. The initial velocity of the stone, u = 0.
Height of the tower, y = 100 m
Let the depth of the well be d.
Time taken of the drop of the stone, t = 5 s
The stone falls under acceleration due to gravity g = 9.81 m/s²
We will use second equation of motion:
s = u t + 0.5 g t²
⇒100 m + d = 0 + 0.5 × 9.81 m/s²× (5.00 s)²
⇒d = (122.6 - 100) m = 22.6 m ≅ 22.5 m
Thus, the correct option is A. The depth of the well is 22.5 m.
Answer:
45000 Kg.m/s
Explanation:
change in momentum = m( v¹-vi)
=3000(25-10)
= 45000
Answer:
X = 6910319.7 m
Explanation:
let X be the distance where the acceleration of gravity is 85% of what it is on the surface and g1 be the acceleration of gravity at the surface and g2 be the acceleration of gravity at some distance X above the surface.
on the surface of the earth, the gravitational acceleration is given by:
g1 = GM/(r^2) = [(6.67408×10^-11)(5.972×10^24)]/[(6371×10^3)^2] = 9.82 m/s^2
at X meters above the earth's surface, g2 = 85/100(9.82) = 8.35m/s^2
then:
g2 = GM/(X^2)
X^2 = GM/g2
X = \sqrt{GM/g2}
= \sqrt{(6.67408×10^-11)(5.972×10^24)/ 8.35
= 6910319.7 m
Therefore, the acceleration of gravity becomes 85% of what it is on the surface at 6910319.7 m .
