Last Problem:
A large stone is 100 times heavier than a small stone, but when dropped at the same time, they fall with the same acceleration (ignoring air resistance). This is a lesson we all learned in 5th grade.
Why doesn’t the large stone accelerate faster? Is it because of its weight, its energy, its surface area or its inertia perhaps?
Answer:
It does seem odd that the heavier object does not fall faster than the lighter object, but experiments prove this to be false. (You may have done your own experiments when you were younger!).
Newton’s second law of motion shows that acceleration is directly proportional to force (weight in this case) and inversely proportional to mass. The equation is:
a = f/m
where:
a = acceleration
f=force
m=mass
Resistance to motion due to mass is called inertia. Therefore, even though a large stone may weigh 100 times more than a small stone, it has 100 times more mass (and inertia). Thus, the two factors cancel each other out.
Ignoring air resistance (which can be a factor for lighter objects), acceleration of every falling body near sea level is 32 feet per second.
Today’s Problem:
If you drop a coin and a small slip of paper at the time, the coin will inevitably reach the ground at the same time. The coin lands on the ground first because of air resistance which slows the descent of the paper.
Figure out a way to demonstrate that the coin and the paper ought to fall at the same rate as the paper in the absence of air resistance, even in a normal room on the earth. The room is on the earth, not the moon!