Crude oil, coal, natural gas. All of these pollute the Earth when there are consumed and have a certain amount available. Renewable resources are infinite in value.
Basically, gravity is dependent on mass, where all things – from stars, planets, and galaxies to light and sub-atomic particles – are attracted to one another. Depending on the size, mass and density of the object, the gravitational force it exerts varies. And when it comes to the planets of our solar system, which vary in size and mass, the strength of gravity on their surfaces varies considerably.
For example, Earth's gravity, as already noted, is equivalent to 9.80665 m/s2 (or 32.174 ft/s2). This means that an object, if held above the ground and let go, will accelerate towards the surface at a speed of about 9.8 meters for every second of free fall. This is the standard for measuring gravity on other planets, which is also expressed as a single g.
Answer:
b. K = U
Explanation:
In this case you have that there are no non-conservative forces over the pendulum. Hence, the total mechanical energy if the pendulum must conserve. You take into account that the potential and kinetic energy of a pendulum are given by:

m: mass of the pendulum
h: height of the pendulum
v: speed
In each moment of the trajectory of the pendulum ET does not change.
You have that, at the lowest point U=0J and for the highest point K=0J. For that point K=ET and U=ET respectively.
Hence, for a mid-way between those points it is necessary that:
b. K = U
Answer:
Sodium is stored under paraffin oil
Explanation:
Group 1 metals are known to be very highly reactive. The chemical reactivity of the members of the group decreases down the group.
Sodium reacts violently with water and upon exposure to the atmosphere. As a result of this, it must be stored under paraffin oil.
Answer:
The centripetal force acting on the car is proportional to the mass of the car.
Explanation:
Let,
The mass of the car be 'm'
The velocity of the car moving in the curved path be 'v'
The radius of the curved path be 'r'
According to physics, a body moving ion circular path experience a force directed along the radius of the path. This force is called centripetal force.
The formula for centripetal force is,
<em>F = mv²/r</em>
Where,
a = v²/r
So, if the mass of the car changes, the centripetal force also changes proportionally according to the above equation.