<span>Some geographic areas endure cycles between these two processes called transgressive-regressive sequences. The rocks of western Pennsylvania are one example. Sandy beaches often leave observable records of transgression by covering marsh sediments that were once behind it as it moves inland. The original sediments are then covered by even deeper water sediments, which geologists can trace and record. It is generally believed that transgression will increase in accordance with rising sea levels worldwide</span>
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: 37.5 nm
Explanation: speed of light c= 3.00·10^8 m/s.
I use same accuracy to speed of light as it's for frequency.
Frequency f= 8.01·10^15 1/s
Speed c = wavelength · frequency
Wavelength = c/f = 3.745·10^-8 m
Answer:
The average velocity of the sled is vavg = s/t.
Explanation:
Hi there!
The average velocity is calculated as the traveled distance over time:
vavg = Δx/Δt
Where:
vavg = average velocity.
Δx = traveled distance.
Δt = elapsed time.
We already know the traveled distance (s) and also know the time it takes the sled to travel that distance (t). Then, the average velocity can be calculated as follows:
vavg = s/t
Have a nice day!
