Answer:
The kinetic energy of the two stones is 320 J
Explanation:
Kinetic energy is the energy that a body possesses due to its movement. So it is the capacity or work that allows an object to go from being at rest, or still, to moving at a certain speed.
In other words, the kinetic energy of an object is that which is produced due to its motion and depends on its mass and velocity as follows:

where the kinetic energy Ec is measured in joules (J), the mass m is measured in kilograms (kg) and the velocity v in meters/second (m/s).
In this case you know that a 20 kg curling stone is sliding in a positive direction at 4 m/s. So:
Replacing you have:

Ec₁= 160 J
A second curling stone slides at the same speed but in the opposite direction. So:
Replacing you have:

Ec₂= 160 J
The kinetic energy of the two stones is calculated as:
Ec= Ec₁ + Ec₂
Ec= 160 J + 160 J
Ec= 320 J
<u><em>The kinetic energy of the two stones is 320 J</em></u>
Answer:
Refracted (refraction) – the bending of transmitted light as it travels across the boundary of one material into another material in which it's speed is different. Unlike diffraction, this change in direction of light occurs because light is changing its speed in the different substances in it traveling in.
Explanation:
Hope it helps
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