A light-year is how astronomers measure distance in space.
-Light can travel 300,000 kilometres in one seconds!
Light year is the distance that light travel can travel in one year.
-Light can also travel 9,00,000,000,000 kilometers.
-One light is about 10 trillion km.
-Almost 300 years ago ,a Danish scientist named olaus roemer,was the fist man to estimate the distance light travels in a year -and using that he figure out the approximate speed of light!
This would be called the "Escape Velocity "
Answer:
Force
If you're taking classical physics, simply stated, a force is a push or a pull of some sort. But there is one other very important thing to understand about Force. A true Force is always an interaction (at least from a classical perspective). That means that forces always come in pairs. This is stated in Newton's Third Law (equal and opposite forces). Every action must have a reaction. This is required for all true forces. Another consequence of this is that force is a vector, meaning it has a magnitude and a direction. The action and reaction will always be opposite in direction.
A lot of people will say F=ma. This is true. However, it is important to keep in mind that this definition is a calculational tool. It is more precise to say the Sum of all forces=ma. The point is that ma is not a force. Forces are things like weight, tension, normal, friction, gravity, electrostatic, magnetic, and various other applied forces. The sum of forces on an object equals the product of its mass times its acceleration.
It is important to keep in mind that the force is on the object that accelerates. Another way to state this is that objects cannot accelerate themselves. You cannot push yourself back (or forwards). But if you push a heavy object like a desk forwards, then the desk can push you back.
Energy
There are many kinds of energy. There are two important things to know.
Energy is the ability to do work. It doesn't mean work is being done, but that work can be done. (So you can see there is an intimate relationship between work and energy).
Energy is conserved. That means the total amount of energy is always constant. If the energy is a system changes somehow, that means some work was done in order to move the energy from one system to another.
Energy is also a scalar (given that Work is a scalar).
Answer:
Explanation:
Kinetic energy is energy due to motion. The formula is half the product of mass and velocity squared.
The mass of the roller coaster car is 2000 kilograms and the car is moving 10 meters per second.
Substitute these values into the formula.
Solve the exponent.
- (10 m/s)²= 10 m/s * 10 m/s= 100 m²/s²
Multiply the first two numbers together.
Multiply again.
- 1 kilogram square meter per square second is equal to 1 Joule.
- Our answer of 100,000 kg*m²/s² is equal to 100,000 Joules.
The roller coaster car has <u>100,000 Joules</u> of kinetic energy.
This is your perfect answer
The base unit for time is the second (the other SI units are: metre for length, kilogram for mass, ampere for electric current, kelvin for temperature, candela for luminous intensity, and mole for the amount of substance). The second can be abbreviated as s or sec.
