I came across the following question in my physics textbook and wanted to try to solve it:
A 1700 kg car is towing a larger vehicle with mass 2400 kg. The two vehicles accelerate uniformly from a stoplight, reaching a speed of 15km/h in 11 s. Find the force needed to accelerate the connected vehicles, as well as the minimum strength of the rope between them.
I did get the correct answer after a while by finding Acceleration (which was
0.3788m/s^2and then multiplying it by the mass of the truck, which was
2400kg. (The answer should be 910 N)
The part that I don't understand (and I had trouble finding the answer because of this very reason) is: Why is the mass not the sum of both masses of the car AND the truck? Should it not be both, as it specifically mentions that they are tied together, and therefore they technically act as one whole system?