# Does a heavier object fall quicker?

Surprising as it might seem, an object’s mass has no impact on how fast it falls. Instead, its speed is determined by a property of gravity called gravitational acceleration (or g for short), which is 9.81 metres per square second at the surface of our planet. This means that in one second, any object’s downward speed will increase by 9.81 metres (32.2 feet) per second because of gravity, regardless of mass. Having said that, if you imagine dropping a feather and a hammer at the same time, you don’t need to be a physicist to guess that the hammer will fall faster (mind your toes!). Gravity accelerates both objects at the same rate, but another factor comes into play: air resistance. The feather is slowed down more by the air and floats down gently, while the hammer crashes straight to the ground.

Apollo 15 astronauts tried out this exact experiment on the Moon where there is no air, and consequently no air resistance – both hammer and feather landed at the same time. Back here on Earth, if you dropped two objects with exactly the same shape and volume but different mass, they would also fall at the same speed.

• G1408

This statement is wrong: Back here on Earth, if you dropped two objects with exactly the same shape and volume but different mass, they would also fall at the same speed.

Mass does matter

The governing equation is

W-D = F where W = weight and,D = drag force, F is resultant force

F = Ma where M is mass, and a is resultant acceleration

W – D = Ma

Terminal velocity is the maximum velocity an object reaches when falling through a fluid, and it occurs when the drag force and weight are equal

W = D

W = Mg where M = mass, and g = gravitational acceleration

D = (0.5)*C*p*A*V^2 where C is the drag coefficient, p is the density, A is surface area and V is the velocity

If A, C, P are all the same for two different objects, but M is different, the heavier object will have a larger terminal velocity than the light object.

Also, volume doesn’t necessary matter, surface area does, and length cause of the skin friction, but not volume, at least not directly

The only time two objects of different mass will fall at the same rate is if there is no drag, an example would be the moon, where there is no atmosphere or any fluid acting on the body

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