If you were floating in space, you would weigh virtually nothing. Yet, you would still have body mass.  The measure of matter, or mass, in English is the slug, and the measure of mass in the metric system is the kilogram.

To calculate the force due to gravity between two objects, the equation below can be used.  The variable force is equal to the Gravitational Constant multiplied by the two masses divided by the square of the distance between the two masses.  The Universal Gravitational Constant, given as G, is a measure of the strength of gravity.  Due to the difficulty involved with observing gravity, the constant has been measured with by far the least precision of all Universal Constants.

But what does force have to do with speed? An answer that any Physicist will give you, is that Force is equal to mass multiplied by acceleration.  This law is universal and should be memorized!

The velocity of an object is defined as the change in position divided by the change in time. Acceleration is defined as the change in velocity divided by the change in time. The "change in" something is denoted by the delta symbol (looks like a d).  Note that s stands for position.

Quantities of velocity are measured in rates: miles per hour or meters per second. Quantities of acceleration are measured in distance per time per time, such as meters per second per second.

More will be added shortly!

• Gravity - from Eric Weisstein's World of Physics
• Cutnell & Johnson's Physics - Fifth Edition hardback