BeginnerTopic 21 of 106Engineering Mechanics
Kinematics of a particle
Describes position, velocity and acceleration without considering forces.
In depth
Kinematics describes position r(t), velocity v=dr/dt and acceleration a=dv/dt without forces. Graphs: slope of x-t gives v, slope of v-t gives a, area under v-t gives displacement. Motion can be rectilinear or curvilinear.
Key points
- Distinguish distance from displacement
- Speed is scalar, velocity is vector
- Differentiate and integrate to move between them
ExampleA car with v=10+2t has a=2 m/s².
What is Kinematics of a particle?
Describes position, velocity and acceleration without considering forces.
Why is it important to understand kinematics of a particle?
Kinematics describes how bodies move without the cause of motion, and it is the first step in predicting positions and speeds for any machine.
What is the difference between speed and velocity?
Speed is the magnitude only. Velocity includes direction, so a car turning a corner has constant speed but changing velocity.
Why are position, velocity and acceleration linked by derivatives?
Velocity is the rate of change of position, and acceleration is the rate of change of velocity, so each is the derivative of the one before.
How is Kinematics of a particle used in practice?
Typical applications include tracking the position of a lift car over time from its speed profile, estimating the speed of a runner's stride from video and planning the travel of a robot arm to a target point.
What should I learn before Kinematics of a particle?
Study "Parallel axis theorem" first (topic 20 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
What are the key points of Kinematics of a particle?
Distinguish distance from displacement. Speed is scalar, velocity is vector. Differentiate and integrate to move between them.
Can you give an example of Kinematics of a particle?
A car with v=10+2t has a=2 m/s².
What comes after Kinematics of a particle?
The next topic is "Uniform acceleration equations", which builds directly on this one.
How difficult is Kinematics of a particle?
It is classed as Beginner in Engineering Mechanics (topic 21 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.