The Force of Gravity

Let us  recall two basic terms before we start:

• mass - a scalar quantity - the amount of substance in an object - measured with a scale or balance in kg

• Force of gravity - a vector quantity - the weight of an object or the force of attraction with which an object falls down to Earth - measured with a spring scale in N (Newtons)

Step 1. Let's measure the mass (m) of two apples  with a balance and then their respective forces of gravity (F_g) with a spring scale

Object	Mass		Force of Gravity
	grams	kilograms	Newtons
Red Apple		0.256 kg	2.50 N
Green Apple		0.136 kg	1.40 N

Step 2. We organize the data in a table

Step 3. We plot the date (recall that mass (m) should be on the x-axis because it is the independent variable) and we draw the line of best fit. 

Step 4. We calculate the slope of the line - Note that m vs. F_g yields a linear relationship

From this graph, which is of the form y = kx, (where k is the slope of the line) we can deduct a simple equation that relates the force of gravity F_g with the mass m.  This simple equation is:

Fg = k m

k is the slope of the line and is a constant value of 9.17 N/kg

Step 5. We test this value against a controlled, known value for accuracy.

Conclusions:

1. Any object (regardless of its mass) experience a force of gravity nearly 10 times the value of its mass.

2. This is due to a constant gravitational field intensity (or acceleration due to gravity) around the surface of the Earth.

3. The accepted (tested) value of this constant is 9.81 N/kg or 9.81 m/s².

   Please Report any problems about this web site to webmaster@dotcomenterprises.net