Answer:
Subduction of the Juan de Fuca plate causes melting and magma generation in the mantle which rises to the surface to create the Cascade volcanoes.
Explanation:
I think you forgot to give the options along with the question. I am answering the question based on my knowledge and research. It is <span>possible to tell if objects in space are moving closer to us or farther away based on several procedures like parallax and standard candles. I hope the answer has come to your help.</span>
The answer is C. in sort of a way. You can't technically see black matter. However, it is holding the galaxies together.
Gravity on the surface = 4 m/s^2
Now, the acceleration due to centripetal motion, a = v^2/R
Where,
v= 10^3 m/s, R = 10^6 m
Then,
a = (10^3)^2/(10^6) = 1 m^2/s
The net gravitational acceleration = 4-1 = 3 m/s^2
The reading on the spring scale = ma = 40*3 = 120 N