A population of mammals leaves an ecosystem because of increased temperatures and decreased rainfall. What’s the reason for this
2 answers:
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Answer:
Friction between the box and the floor is 25N to the left
Explanation:
There are two forces acting on the box along the horizontal direction:
- The force of push applied by the worker, in the forward direction, F
- The force of friction, , acting in the opposite direction (backward)
So the net force acting on the box is
According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:
And so
However, in this case the box is moving at constant speed; this means that its acceleration is zero:
Therefore we have:
Which means
And since we are told that
This means that the force of friction is also 25 N:
Answer:
Law of refraction
Explanation:
An experiment to analyze the refraction of light in water can easily be performed with a laser pointer and protractor.
We throw the fishing rod line into the water, place the protractor at the point where the line touches the water and use the direction of the line for the direction of the laser pointer (on), the laser is visible by the reflection on the particles in the air.
The vertical line is called Normal and all angles must be measured with respect to this reference in optics.
Having these angles and the refractive index of water we can use the law of refraction
n₁ sin θ₁ = n₂ sin θ₂
θ₂ =
we can repeat several times to analyze several different input points (different angles) and to decrease the errors in the measurements.
the refractive index of air is n1 = 1 and n2= 1.33 (water)