As per the question the mass of the boy is 50 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Hence the weight of the boy
[m is the mass of the body]
we have m = 50 kg.
Hence w = 50 kg ×9.8 m/s^2
=490 N kg m/s^2
= 490 N
Here newton [N] is the unit of force.
Answer:
mesa
Explanation:

A mesa is a flat-topped mountain or hill. It is a wide, flat, elevated landform with steep sides. ... Spanish explorers of the American southwest, where many mesas are found, used the word because the tops of mesas look like the tops of tables.
By combining blue with yellow light is like combining blue light with red and green light. The result of combining these three primary colors of light is to produce white light.
<h3>What is laundry bluing ?</h3>
Laundry bluing is a product adds a trace amount of blue dye to white fabric during laundering to improve its appearance.
Bluing products in higher concentrations can darken jeans and other blue cloth.
The blue overpowered the yellow to reflect white (at least the appearance of white to the human eye).
Blue and yellow are complementary colors that combine to reflect white, Fabrics.
Here,
Yellow light is a combination of red and green light. So combining blue with yellow light is like combining blue light with red and green light. The result of combining these three primary colors of light is to produce white light.
Learn more about White light here:brainly.com/question/16317768
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One way of removing nitrogen gas from the atmosphere is by natural nitrogen fixation. This is done by nitrogen-fixing bacteria in the oceans and in the soil. Nitrogen fixation is a process that converts the nitrogen in air to ammonia.
Answer:
Explanation:
Given
mass of box 
coefficient of kinetic friction 
coefficient of Static friction 
cart is moving with constant velocity therefore Net Force is zero
Since there is no net acceleration therefore friction force will be zero
mathematically

where 


