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My physics core is a little bit weak, and this one question confuses me.
A 3kg box sits on top of a 7 kg box. The object accelerates at 1 m/s^2. Find the force applied on the bottom block; if there are no forces besides this one.
F= ma
So, my initial attempt was F = m * a. m = 7kg + 3kg = 10 kg. F = 10 N.
However, this is incorrect. The answer is supposed to be 3 kg. They only take the bottom block into account and this is extremely confusing for me. Of course, this is from an even larger kinematics question; but this is the only step I do not understand. And it's basically exactly the same as the one I'm asking now.
Why do we use 3 kg, and not 10 kg?
Homework Statement
A 3kg box sits on top of a 7 kg box. The object accelerates at 1 m/s^2. Find the force applied on the bottom block; if there are no forces besides this one.
Homework Equations
F= ma
The Attempt at a Solution
So, my initial attempt was F = m * a. m = 7kg + 3kg = 10 kg. F = 10 N.
However, this is incorrect. The answer is supposed to be 3 kg. They only take the bottom block into account and this is extremely confusing for me. Of course, this is from an even larger kinematics question; but this is the only step I do not understand. And it's basically exactly the same as the one I'm asking now.
Why do we use 3 kg, and not 10 kg?