By Newton's second law, we have

So, in order to give a 0.15kg body an acceleration of 40m/s^2, you need a force of

Sound travels fastest through matter in the <em>solid state</em>.
I know this from having answered a huge number of Brainly questions that required me to look up things like this:
-- Speed of sound in air . . . about 340 m/s
-- Speed of sound in sea-water . . . about 1,500 m/s
-- Speed of sound in steel . . . about 5,960 m/s
Answer:
D. s=3x+4y
Explanation:
The line is at the 3rd column in the 4th row.