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>
Couple examples of protists are Quartan Malaria, Plasmodium Falciparum, and Babesia Canis
Explanation:
Lead(II) phosphate is an ionic compound with chemical formula Pb3(PO4)2. Lead(II) phosphate is a long-lived electronically neutral reagent chemical.[1] Despite limited tests on humans, it has been identified as a carcinogen based on tests on animals conducted by the EPA.[2] Lead(II) phosphate appears as hexagonal, colorless crystals or as a white powder. Lead(II) phosphate is insoluble in water and alcohol but soluble in Nitric acid (HNO3) and has fixed alkali hydroxides. When lead(II) phosphate is heated for decomposition it emits very toxic fumes containing Lead (Pb) and POx.[3]
Compounds that has two elements on the formula can be bonded by ionic or covalent bond. If the compound is a metal and a non-metal then it will be ionic bonding. However, when it involves two non-metals, then it will have covalent bonding.