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Answer: The nearest position of an object from a normal human eye so that its image is formed on retina is 25 CM. If the object is placed at a distance less than 25 CM, then the blurred image of the object is formed on retina as the focal length of a lens cannot be decreased below a certain limit. Hence we cannot see it clearly.
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The moon is moving away from Earth at a rate of approximately 3.78 cm per year.
This migration of the Moon from the Earth is mainly due to the action of the Earth tides. It can be explained as follows:
- the Moon exerts a gravitational force on the Earth, which is stronger at the Equator (since the Equator is closer to the Moon), creating the tides
- However, the Earth rotates faster on its axis (one rotation every 24 hours) than the Moon (one rotation every 27 days), therefore the tidal bulge on Earth tries to pull the Moon "ahead" in its orbit. As a result, the Moon tends to sped up.
<span>- As opposite reaction, the Earth tends to slow down in its rotation, with a loss of angular momentum. Since the angular momentum must be conserved, the radius of the orbit of the Moon becomes larger, and this explains why the Moon is moving away from the Earth.</span>
Answer:
<h3>4905N</h3>
Explanation:
The force needed to keep the elephant from slowing down is expressed as shown according to Newtons second law of motion.
Force = mass * acceleration due to gravity
Given
Mass of elephant = 500kg
acceleration due to gravity = 9.81m/s²
Force = 500*9.81
Force = 4905N
<em>Hence the force needed to keep the elephant from slowing down is 4905N</em>
Answer:

Explanation:
Let's start by writing the equations of the forces along the two directions:
- Vertical:

where
N is the normal reaction
is the angle between the road and the horizontal
(mg) is the weight of the car, with m being its mass and g the acceleration of gravity
- Horizontal:

where
v is the speed of the car
r is the radius of the turn
Dividing the 2nd equation by the 1st one, we get:

In this problem:
(radius of the turn)
is the speed

Substituting, we find:

Momentum = mass x acceleration
5 x 2 = 10 kg. m/s