The intensity on a screen 20 ft from the light will be 0.125-foot candles.
<h3>What is the distance?</h3>Distance is a numerical representation of the length between two objects or locations.
The intensity I of light varies inversely as the square of the distance D from the source;
I∝(1/D²)
The ratio of the intensity of the two cases;
Hence, the intensity on a screen 20 ft from the light will be 0.125 foot-candles
To learn more about the distance refer to the link;
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a)
b) 1.96 N
c) 1.96 N
Explanation:
a)
To find the box's acceleration, we have to find first the net force acting on the box in the horizontal direction.
We have:
- The forward force of 3.55 N
- The backward, resistive force of 0.52 N
So, the net force forward is
Now we can find the acceleration by using Newton's second law of motion, which states that:
where
m = 0.200 kg is the mass of the box
a is its acceleration
And solving for a, we find the acceleration:
b)
The gravitational force on an object is the force with which the object is pulled towards the ground by the Earth.
It is given by
where
m is the mass of the object
g is the gravitational field strength
In this problem we have
m = 0.200 kg is the mass of the box
is the gravitational field strength
So, the gravitational force on the box is
c)
The normal force is the reaction force exerted by the floor on the box, in the upward direction.
In order to find the magnitude of this force, we apply Newton's second law of motion along the vertical direction.
We have two forces in this direction:
- The gravitational force, W, downward
- The normal force, N, upward
So the net force is
According to Newton's second law,
However, the box is at rest in the vertical direction, so the vertical acceleration is zero:
This means that the net force is zero:
And so, we can find the normal force: