Here we find a missing force by using the acceleration. In the overhead view of Figure 5-4a, a 2.0 kg cookie tin is accelerated at 3.0 m/s^2 in the direction shown by, over a frictionless horizontal s

Here we find a missing force by using the acceleration. In the overhead view of Figure 5-4a, a 2.0 kg cookie tin is accelerated at 3.0 m/s^2 in the direction shown by, over a frictionless horizontal surface. The acceleration is caused by three horizontal forces, only two of which are shown: Force 1 of magnitude 10 N and Force 2 of magnitude 20 N. What is the third force in unit-vector notation and in magnitude-angle notation?