Differentiate both (i?and?j) components of the vector
To integrate?a vector:
Integrate both (i?and?j) components of the vector
There will be a constant of integration,?c, which will be a vector made up of two values (an?i-component constant and a?j-component constant)
Find?c?by substituting in any known vectors, in the same way as you would if it were in 1D
Find the separate components of the vector?c?by equating the?i-components and the?j-components separately
How does calculus link to kinematics?
In 2D we normally use the vector?r?to represent displacement instead of s
Just like in 1D:
Differentiate?displacement to get velocity and velocity to get acceleration
Integrate?acceleration to get velocity and velocity to get displacement
Harder problems involving vectors, calculus, position vectors and F=ma
Harder problems could involve:
using Newton’s Second Law (N2L)?F = ma
two vectors being equal requiring both?i?and?j?components to be equal
exponentials, logarithms, trigonometric functions (not just polynomials)
suvat equations (in vector form) would only be involved if?acceleration is constant
You may have to find the?magnitude?of the vectors
The magnitude of the?velocity?is the?speed
The magnitude of the?displacement?is the?distance?from the?starting point
The position vector of a particle is?r = r0?+ s
r0?is the?initial position?of the particle
s?is the?displacement?of the particle from its initial position
Worked Example
Exam Tip
If the question refers to the direction that the particle is travelling, then you would use the velocity. If the?direction?of?motion?is asked for then it should be clear from the question whether they want an angle, bearing or vector which it is parallel to.