i have this Physics question from my teacher that says:

'Dogs are pulling a sled on the snow. If the dogs have stopped pulling draw the force diagram'

Well apparently the question only had three forces - gravity (pulling down), reaction forces (arrow going up), and friction (pulling the opposite directiong of the sled).

Well we also learnt that forces come in pairs so can someone please explain how this is possible. And if it is not can you please give the correct answer as I also put the force inertia which is currently wrong...