Answer:
0.07142 m/s in the opposite direction of the bullet
Explanation:
= Mass of rifle = 70 kg
= Mass of bullet = 0.01 kg
= Velocity of rifle
= Velocity of bullet = 500 m/s
As the momentum of the system is conserved

The recoil velocity of the rifle is -0.07142 m/s
The negative sign shows the opposite direction of the rifle.
<h2>Answer: Venus</h2>
Galileo was the first to use the telescope to observe the heavens, mainly observing the Moon, the Sun with its sunspots, Jupiter with its moons and Venus (in the early 1600s).
In the case of Venus, he observed that it presented phases (such as those of the moon) together with a variation in size; observations that are only compatible with the fact that Venus rotates around the Sun and not around Earth.
This is because Venus presented its smaller size when it is in full phase and the largest size when it is in the new one, when it is between the Sun and the Earth.
These images along with other discoveries were presented to the Catholic Church (which supported the <u>geocentric theory</u> for that time) as a proof that completely refutes Ptolemy's geocentric system and affirms <u>Copernicus' heliocentric theory.</u>
Exothermic because exothermic reactions transfer energy to the surroundings. Endothermic reactions take in energy from the surroundings, so if you want to warms people's hands you should use exothermic chemical reaction for the product.