Step on the “Gas!” What happens?

You go faster don’t you? There is another name that we give to this change in speed, it is also known as? Acceleration! The definition of “Acceleration” is the same as what all of us have experienced at some point in our lives, A change in the rate of speed.

Another way of stating this is -- Acceleration is the amount that your speed changes compared to how long it takes. If you have an acceleration of 1m/sec, that means that for every second that you are in motion, your instantaneous speed increases by 1m/sec. –Start at a speed of zero, with the acceleration of 1m/sec, after 10 seconds how fast are you going? 10m/sec!

Acceleration takes energy to accomplish. Sometimes that energy is rather self evident, gasoline for example provides the energy for the acceleration that we need in our cars. But what about the acceleration that occurs when something is dropped or goes downhill? Extreme Mountain Bike Crash with 170 kph –When you drop something the speed definitely changes! It starts perfectly still and gets faster and faster the farther and farther away it gets from wherever it began. What provides the energy for this type of acceleration?

Sir Isaac Newton came up with the explanation for this form of energy. Gravity! Gravity provides the energy for the acceleration from rest for those objects that have been dropped. This is shown by a constant rate of acceleration that all of you MUST COMMIT TO MEMORY!

The constant for the acceleration due to gravity is m/sec 2 or 10m/sec 2

Gravity never changes as far as we on Earth are concerned. Can you think of someplace where this constant will change? –When we start getting into “Outer Space” you see a change in this constant due to the fact that you are getting farther and farther away from the source of the gravitational energy, which is the center of our planet. Every “Heavenly Body,” or matter for that fact, can exhibit the energy known as gravity. –By Heavenly Body we are talking about those things found outside of our own planets realm.

Things like comets, asteroids, stars, moons, etc. they all exhibit a gravitational pull. Asteroid (and Comet) groups But more about that later!

Now that we have established the fact that the constant for Gravity cannot change. Can other things that are effecting acceleration itself change the rate at which the speed of that object in question can change? HUH? Can we change the speed of a body by changing its acceleration?

Yes we can! And this is where we will leave off for tomorrow!