When magnets come within the magnetic fields of other magnets, they move toward or away from each other, depending on their poles. The door latch shown in the picture is one of many ways magnets can be used in everyday life. How are magnets most likely used in this latch?

A) Magnets with opposite poles are attached to the door and floor, when they come in contact, they attract one another and latch the door.
B) The magnets are extremely heavy, so when the door is open, the latch on the floor pulls on the magnet, making the door too heavy to close.
C) The door magnets are turned on and off by the switch on the floor. When the door is over the latch, the magnets turn on, latching the door in place.
D) Magnets with similar poles are placed on the floor latch and on the door, which attract one another when they are close, latching the door in place.

The answer is A

Explanation:

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.