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How to Solve Newton’s Second Law Problems

Newton's Second Law Problems

Scope of the Newton’s Second Law Problems:
Generally, the problem asks about forces or accelerations

How to attack Newton’s Second Law Problems
1) Draw one free body diagram for each object in the problem

Read the following two posts to get the feel about the free body diagram

Different Types of Force and There Origin
How To draw Free Body diagram

Read the below Video for a Free body diagram also

Another important note on identifying the force
a) if the Object is touching a surface, There is a normal force for every surface touched. Normal acts from the surface through objects perpendicular to the surface of contact . The normal force is zero if and only if the object loses contact with the surface

b) If the Object is on a rough surface, There is a frictional force point along the surface , If the object slides over the surface, there is kinetic or sliding friction, If the object does not slide relative to the surface, there is static friction

c) If the Strings or ropes are attached to the object, There is a tension force. Ropes and strings can only pull . The direction of tension is from the object along the string

2) Decide on a direction for the acceleration of each object
3) Choose axes such that one axis points in direction of the acceleration since a good choice of coordinates makes the problem easy to solve
4) Determine the x and y components of each force
5) Get an equation for the x components for each object using?Fx=max
6) Get an equation for the y components for each object using?Fy=may
7) Be careful of signs. Be consistent.
8) Solve the problem for the unknown

Some More Tips
1) It is helpful to put numbers at the end and solve the problem with the alphabet till the end
2) Be sure to keep track of the units. It should be the same on LHS and RHS
3) Always check the answer for dimensional accuracy
4) use symmetry present to simply the problem and calculation

Watch the below on How to solve the force problem

Read the full-length Notes at the below Link

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