Please help me answer a physics question

Loaf | Legendary Invincible!
 
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So, I'm reading a brief history of time, and I'm at the part where it's describing newton's second law of motion. It's a bit hard to understand these concepts without being able to visualize them, but none the less I was wondering if an object accelerates slower proportionately to it's weight, then does that same principle apply to an object that's in outer space where isn't being counteracted by the friction of the ground under it? Like, I imagine a huge airplane trying to lift off, and it obviously will go a lot slower with the same engine as a much smaller plane, because it has more matter to move. But would that same airplane accelerate at a high speed in outer space, at the same speed as a smaller plane would with that smaller engine that was faster on earth?


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But would that same airplane accelerate at a high speed in outer space, at the same speed as a smaller plane would with that smaller engine that was faster on earth?

No. F=ma

a = constant (in your scenario)

As m increases (for the heavier plane), the force required to move it at the same rate increases.

Easy numbers example: Plane A weighs 2 tons, Plane B weighs 4 tons. You want to accelerate them at 8 meters per second per second.

Plane A:  F = 2*8 = 16m/s/s
Plane B: F = 4*8 = 32m/s/s

Friction is not the main impulse behind Newton's Second Law, it just increases it (hence why it's a coefficient of the normal force, and not a unit value). The example above was in space, with no friction. On Earth, the forces required to move both planes would be larger, and still unequal. On Earth, it would look something like:

Plane A:  F = 2*8 = 16m/s/s + Ff_A
Plane B: F = 4*8 = 32m/s/s + Ff_B
Last Edit: December 02, 2016, 03:54:40 PM by HubbleTurkeyscope


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Thank you.