Proportional Masses Newtons Laws

[destro47]

A red box and a blue box sit on a horizontal, frictionless surface. When horizontal force F is applied to the red box, it accelerates 4.88 m/s2.

a) If F is applied to the blue box, it accelerates at 1.32 m/s2. What is the ratio of the masses of the boxes (mass of the red box/mass of the blue box)

b) Now, the two boxes are glued together. If F is now applied to the combination, what is the acceleration of the boxes?

Got the answer to part a, turns out its .270

My question is how do we use this info to solve part b. I have a sneaking suspicion that the solution to this is the sum of the accelerations, multiplied by the ratio of the masses.


F= (m1 + m2 )[(4.88 = 1.32)(.270)]

The part in brackets is the mathematical representation of what I'm talking about here.

Let me know if I'm on the right track with this please, I only have a limited number of times to submit the answer for my physics homework.

 

[member 553083]

Yes, you are on the right track. The acceleration of the combination is the sum of the accelerations of the individual boxes multiplied by their ratio of masses. So, the acceleration of the combination is given by:a = (4.88 + 1.32) × 0.270 = 2.06 m/s2