The Difference Between Mass and Weight

There is a common perception that weight and mass are basically the same thing. This video aims to tease out the difference between mass and weight by asking people what makes a car difficult to push. The standard answer is that it is difficult to push because it's heavy. But heaviness is a measure of weight, the gravitational pull of the Earth attracting the car to Earth's center. When the car is pushed on a flat road, the force of gravity does not oppose the motion. Instead the resistance felt is an indication of the car's mass which determines its inertia. Inertia is the property of matter that means it tends to resist acceleration - the greater the mass, the less the acceleration for a given amount of force.

Category:

Education

Tags:

• mass vs. weight
• weight vs. mass
• mass
• weight
• inertia
• public awareness of science
• forces
• gravity
• heavy
• Newton's Laws
• science literacy

[Ululuro]

Does that mean that the car is still easy to push, even if the gravitational pull of the earth would be 100x greater?

[1veritasium]

@Ululuro Yes! as long as your car has good bearings, e.g. not a lot of rolling friction.

[simoncapon]

RIP derek's old car.

[1veritasium]

@simoncapon haha, yeah it was a good car - I'll miss it. The top is broken on my new one. I need to get it fixed.

[ghrpdx]

I thought the answer was, "Because the parking brake is on."

[Arghira]

If you want to loose weight just go to the Moon =))

[speeps84]

Isn't weight just mg?

[DYLONayms]

@antonio66634 I totally agree those questions are quite obvious, just basic physics. But people are superficial, lazy and not curious about the world they live in (I mean, the Nature) : they prefer believe in something they don't have to understand (like God or magic shampoo lol). That's why the world is becoming a fucking mess. Alleluia

[antonio66634]

Don't u find anyone who knows the correct answer !? Because your asks are pretty "basics" . I mean i know 3/4 of what u ask and i just started college studies ...

[xero907]

I thought you were going to say it was possible to push it because... the car has wheels?

[vilondero]

@Abhibhav14 Mass is always constant. And in the water, the weight seems to change because of buoyancy, but it still keeps the same value.

[1veritasium]

@HeyyLookItsAlex I got the car moving and then tried to stop it. Now friction is helping you but it's just as hard to stop it as it was to get it going. Plus we know that cars have very little rolling friction because they can go quite a ways just coasting.