There is a 33% chance of a large earthquake off the coast of Oregon.
The two main concerns of a large earthquake are Gas fires and Tsunami .
Explanation:
Everytime a large earthquake hits in any other part of the world, We find a small earthquake hitting off the coast of Oregon.
So scientists feel that as United States is prone to Earthquakes, the people have to be prepared for such eventualities.
The main concern for this large earthquake is, that it might lead to gas leakages at homes that can start a gas fire, which might spread. So people have to be careful and check on any gas leakages.
Such large earthquakes can also lead to tsunami waves. So people have to take precautions and evacuate, if they are near the coastline.
Answer:
Option B
Explanation:
Speed of a wave is denoted by:
v=fλ
where f is the frequency which is unchanged 15Hz and λ is the new wavelength which is 28m
v=fλ

Answer:
Tension, T = 87.63 N
Explanation:
Given that,
Mass of the object, m = 6.9 kg
The string is acting in the upward direction, a = 2.9 m/s²
Acceleration due to gravity, g = 9.8 m/s²
As the lift is accelerating upwards, it means the net force acting on it is given by :
T = m(a+g)
= 6.9 (2.9+9.8)
= 6.9(2.7)
= 87.63 N
So, the tension in the string is 87.63 N.
2nd class leaver refers to such leaver in which load lies between effort and fulcrum.In a nut cracker too load is in between effort and fulcrum.Thus, nut cracker is a 2nd class leaver.......