Answer:
Farsightedness (hyperopic)
2.79 D
Explanation:
When a person cannot see something which is close to their eyes this condition is known as farsightedness. She should use a convex lens to correct her eye sight.
u = Object distance = 22-2.7 = 19.3 cm
v = Image distance = -55+2.7 = -52.3 cm
f = Focal length
The power of a lens is given by
The power of her glasses should be 2.79 D
4) none of these matter. with no air resistance, they all hit the ground at the same time.
Explanation:
The motion of the objects is a free fall motion, since the only force acting on them is gravity. Therefore, it is a uniformly accelerated motion with constant acceleration (acceleration of gravity) towards the ground, and so we can find the time of flight by using the suvat equation:
where
s is the vertical displacement (equal to height of the tower)
u = 0 is the initial velocity
t is the time
is the acceleration
Re-arranging the equation.
As we can see, the time of flight depends only on the height of the tower (s) and the acceleration due to gravity (g): therefore, the three objects reach the ground at the same time.
Learn more about free fall:
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Answer:
The magnetic field is
Explanation:
From the question we are told that
The mass of the metal is
The current is
The distance between the rail(length of the rod ) is
The coefficient of kinetic friction is
Generally the magnetic force is mathematically represented as
Given that the rod is moving at a constant velocity, it
=>
Where is the kinetic frictional force which is mathematically represented as
So
=>
substituting values
=>
=>
Answer:
Explanation:
P = Acoustic power = 63 µW
r = Distance to the sound source = 210 m
Acoustic power
Threshold intensity =
Ratio
Ratio of the acoustic intensity produced by the juvenile howler to the reference intensity is 113.68