Answer:
1: Elements are substances that cannot be broken down into more substances.
2: Compounds are a group of elements in a specific ratio.
3: A metalloid is between a metal and a non-metal.
4: A physical property is a property you can see or touch.
5: A chemical property is a property seen in chemical reactions.
6: Alloys are the combination of two or more metals to make a better material.
7: An insulator doesn't let heat and sound escape.
8: Corrosion is when a metal reacts to oxygen, water, or sulfur.
9: Rust is when a metal is exposed to oxygen
Explanation:
The period of a pendulum is given by

since Karachi is near sea level, g is larger than it is on Mt. Everest. That means the pendulum will have a larger period on Mt. Everest than it would in Karachi.
This is a comet. It is also called a dirty snowballs.
Answer:
a) 20s
b) 500m
Explanation:
Given the initial velocity = 100 m/s, acceleration = -10m/s^2 (since it is moving up, acceleration is negative), and at the maximum height, the ball is not moving so final velocity = 0 m/s.
To find time, we apply the UARM formula:
v final = (a x t) + v initial
Replacing the values gives us:
0 = (-10 x t) + 100
-100 = -10t
t = 10s
It takes 10s for the the ball to reach its max height, but it must also go down so it takes 2 trips, once going up and then another one going down, both of which take the same time to occur
So 10s going up and another 10s going down:
10x2 = 20s
b) Now that we have v final = 0, v initial = 100, a = -10, t = 10s (10s because maximum displacement means the displacement from the ground to the max height) we can easily find the displacement by applying the second formula of UARM:
Δy = (1/2)(a)(t^2) + (v initial)(t)
Replacing the values gives us:
Δy = (1/2)(-10)(10^2) + (100)(10)
= (-5)(100) + 1000
= -500 + 1000
= 500 m
Hope this helps, brainliest would be appreciated :)