Applying Newton's Second Law
You'll encounter three main types of Newton's Second Law problems on tests. The first type asks you to find one missing variable when you know the other two. For example, if a force of 88 N causes an acceleration of 4 m/s², the mass must be 22 kg.
The second type involves analyzing free-body diagrams to find net forces. Remember that forces in the same direction add together, while forces in opposite directions subtract. When arrows point in different directions, you need to consider each direction separately.
The third type requires finding unknown forces when you know the net force. For these problems, use what you know about the net force and the known individual forces to determine the unknown forces.
📌 When working with free-body diagrams, always establish a coordinate system (which way is positive) and be consistent with your signs for forces in different directions.
Practice makes perfect with Newton's Second Law! Try problems like finding the acceleration of a 5 kg mass pushed by a 10 N force 2m/s2 or calculating the force needed to accelerate an 8 kg mass at 5 m/s² (40 N). These calculations help you understand how objects move in the real world.