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In scientific calculations on the course, g represents the acceleration produced in a falling object by the effects of gravity.

An object falling toward the ground will accelerate at the rate of 9.81 metres per second, for every second that the object is falling.
This is represented by: g = 9.81m/s/s or 9.81m/s2

Apprentices will use this figure when calculating the weight of an object, given its mass.

For example, to calculate the weight of a 10 tonne machine, we convert the 10 tonne to the base unit of kilogrammes, 10,000 Kg. This is the mass of the vehicle. To calculate the weight, we use the following formula:

W = m x g

W = 10,000 x 9.81

W = 98,100 Newtons, or 98.1KN

Objects dropped on the earth, regardless of their weight, will fall to the ground and hit the ground at the same time. So, in theory, a cannon ball and a feather dropped together, would hit the ground together. Of course, on earth, the atmosphere would distort this experiment. However, on the moon there is no atmosphere to interfere. Even though the moon's gravitational field is only about 1/6th of that on earth, if the theory is correct, the hammer and the feather should hit the ground at the same time. Check out what happened:   

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