Yes the text in the red is correct.
Explanation:
Here we will apply the law of conservation of momentum which is one of the powerful laws of physics. As this law states that the "if no external forces are acting on the system then the net momentum of the system before and after must remain conserved. As the astronaut has a hammer, if he throws it in the direction opposite of his space craft, he will automatically move towards the space craft to conserve the momentum. That's how he can reach the space craft easily by throwing away the hammer.
Answer:
the focal length of the mirror is : 
Explanation:
Use the formula for the formation of image using a divergent mirror and recalling that the image (s') that this mirror formed is virtual, so it is entered as a negative number in the formula. Use the object position (s) as 10, the image position (s') as -2, and derive the value of the focal length:
Johannes Kepler was a main stargazer of the Scientific Revolution known for detailing the Laws of Planetary Motion. A stargazer, obviously, is a man who contemplates the sun, stars, planets and different parts of room. Kepler was German and lived in the vicinity of 1571 and 1630.
Despite the fact that Kepler is best known for characterizing laws in regards to planetary movement, he made a few other striking commitments to science. He was the first to discover that refraction drives vision in the eye and that utilizing two eyes empowers profundity recognition.
