48. Final Velocity Your sister drops your house keys down to you from 4.3 m What is the velocity of the keys when you
catch them?

There is a difference between the words 'drops' and 'throws'

If an object is dropped, it's initial velocity is 0 but if the same object is thrown, it has some initial velocity

Since 'the sister' DROPS the keys, the initial velocity will be 0 m/s

We are given:

u=0 m/s

s = 4.3 m

a = 9.8 m/s/s (gravity)

From the third equation of motion:

v² - u² = 2as

Replacing the known values

v² - (0)² = 2(9.8)(4.3)

v² = 84.28

v = 9.2 m/s (approx)

Hence, the final velocity of the keys is 9.2 m/s

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it