SIMPLIFIED: "2.4: Problem-Solving for Basic Kinematics"

Article Link: https://phys.libretexts.org/Bookshelves/University_Physics/Physics_(Boundless)/2%3A_Kinematics/2.4%3A_Problem-Solving_for_Basic_Kinematics 

Note: The image above is from the original article

There are ultimately four main equations to solve kinematics questions. Here they are:

“V” represents the final velocity of an object. “V₀” represents the initial velocity of an object. “t” represents time, “a” represents acceleration, and “d” represents displacement.

To solve a kinematics question, you will be using at least one of the equations above. Here is the very simple way to solve kinematics questions:

1. Read the problem, and underline everything that the question is telling and asking you. 

2. Look at the choice of equations, and then pick the one that includes all of the variables that the question has given a value for.

3. Solve for the unknown variable.

Here is an example question and a worked out solution: “Caden is driving a car. The car started from rest, and over 10 seconds, Caden covered 20 meters. What was the car’s acceleration?”

Solution: Let’s highlight everything the problem tells you. The problem states that the car started from rest, indicating that the initial velocity is 0 (V₀=0). Next, the problem mentions 10 seconds, meaning time is 10 seconds (t=10). Then, the problem states that the distance covered is 20 meters (d=20). At the end, the problem asks for the acceleration, which is the variable we want to solve for. Since we have V₀, t, d, and we want to solve for a, we look for the equation that has all four of these variables. That equation is equation #3. Since we have picked an equation, you can now plug in the known variable values and then solve for the unknown variable: acceleration. 

Answer: The car’s acceleration is 0.4 meters per second squared.