<span>Scientists have obtained most of this information from natural geological activity.
</span>S-waves and p-waves are seismic waves- the waves of energy that travel through the Earth as a result of an earthquake .Both P- and S-waves travel easily through solids, but S-waves cannot pass through liquids, and they cannot pass through the outer core. Scientists know that Earth’s outer core is liquid because s-waves are not able to pass through it.<span> When an earthquake occurs there is a “shadow zone” on the opposite side of the earth where no s-waves arrive.
</span>So, one of the reasons <span>why scientists believe the outer core is liquid is the s-wave shadow zone.</span>
Instead of asking this question go and study
Answer:
I'm PRETTY SURE your answer is A
Explanation:
let's convert 400 newtons to Kg, which is 40.7886.
now we put it in a formula that includes gravity and acceleration
(40.7886 kg) ( 9.8 m/s2) + (40.7886 kg) (0)
now we come up with the answer of 399.72828 kg or 3920 Newtons
Not sure which unit you are looking for but they are both there.