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Introduction To Kinematics Basic Mathematical Concepts L-2
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Introduction to Kinematics Basic mathematical Concepts
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Some Basic Mathematical Concepts
- When we study kinematics, we do not go in the details of what is causing the motion, but we just analyze the motion. - Planar motion. - To describe position of a point, coordinate system.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Coordinate System
- Cartesian axes (x, y) - We take two mutually perpendicular directions. - x and y are at an angle of 90 degrees to each other. - The intersection of these is called the origin represented by O. - Any point P, which is at a location on the cartesian plane, is described by the coordinates of x and y.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Position Vector
- Position $P$ of a point is given by coordinates$(x, y)$ - $\overrightarrow{O P}$ from origin to length from origin to position of P. - $\overrightarrow{O P} \rightarrow$ Position vector - Lenght $OP \rightarrow$ Magnitude.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Vector
- Vector has 2 characteristics - **1)** Magnitude (length) - **2)** Direction
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Differential Calculus
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Concept of a derivative
- $y=f(x)$, $y$ is a function of $x$. - For different values of x, we have different values of y. - $ P(x, y) $, $Q(x+\Delta x, y+\Delta y)$ - Straight line joining $P Q$ - $\tan \theta=\frac{\Delta y}{\Delta x}$.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Slope of a Curve
- Q approach $P \rightarrow \Delta x \rightarrow 0 , \Delta y \rightarrow 0$. But $\frac{\Delta y}{\Delta x}$ will not approach zero. - PQ approach tangent to the and at point $P$. - If denote slope of line by $m$. - $m=\lim _{\Delta x \rightarrow 0} \frac{\Delta y}{\Delta x}$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Derivative
- Define derivative of a function $y$ where $x$, - Where $y=f(x)$ - $\frac{d y}{d x}=\frac{d f(x)}{d x}=\underset{\Delta x \rightarrow 0}{\operatorname{lim}} \frac{f(x+\Delta x)-f(x)}{\Delta x}$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Properties of Derivatives
- 2 functions, $u(x), v(x)$ - $ \frac{d(u+v)}{d x}=\frac{d u}{d x}+\frac{d v}{d x}$ - $ \frac{d(u v)}{d x}=u \frac{d v}{d x}+v \frac{d u}{d x}$ - $ \frac{d(\frac{u}{v})}{d x}=\frac{1}{v^2} \frac{d u}{d x}-u \frac{d v}{d x}$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Properties of Derivatives
- $\frac{d x^n}{d x}=n x^{n-1}$ - If u = u(x), - Chain Rule: $\frac{d u^n}{d x}=n u^{n-1} \frac{d u}{d x}$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Integral Calculus
- Area between $f(x)$ and $x$ axis before $x=a$ and $x=b$.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Integral Calculus
- Each interval has a length $\Delta {x}_{i}$ - $\Delta A_i=f\left(x_i\right) \Delta x$ - $\text { Total Area }=\sum \Delta A_i$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Integral Calculus
- Total Area $=\sum \Delta A_ i=\sum _ {i=1}^N f\left(x_i\right) \Delta x$ - $N \rightarrow \infty$, $\sum \rightarrow \text { integral } \int$ - $A=\int_{x=a}^ {x=b} f(x) d x =\int _ {a}^{b} f(x) d x$.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Integral Calculus
- Integration $\rightarrow$ Inverse of differentiation. - $g(x)$ such that $\frac{d g(x)}{d x}=f(x)$ - $g(x)=\int f(x) d x $ - $\int_a^b f(x) d x=g(b)-g(a)$
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Properties of Integral Calculus
- $ \int x^n d x=\frac{x^{n+1}}{n+1}+c $ - $ \int \frac{1}{x} d x=\ln x+c $ - $ \int \sin x d x=-\cos x+c $ - $ \int \cos x d x=\sin x+c $
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Particle
- Particle is on entity of very small size (point) but of a finite mass. - Treat cricket ball treated as a particle.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Particle
- If we need overall estimates of path moved by body (without (bothering about details of different parts of the body) $\rightarrow$ lie can treat body as a particle. - Distance moved by body $\gg$ size.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Reference Frame
- **In a reference frame:** - Device to measure length device to measure time (clock) observe motion of a point $P$ in this reference frame.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Reference Frame
- **Reference frame 1**: - Ground car is moving. - **Reference frame 2**: - Car someone sitting on seat of the car.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Reference Frame
- Is any reference from which is absolutely stationary? - Reference frame fixed to car $\rightarrow$ moving w.r.t.ground. - Reference frame fixed to ground, $\rightarrow$ rotating with the earth. - Reference frame to centre of sun.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Velocity And Acceleration
- Path At time t - $\overrightarrow{O P}=\vec{r}(t)$ - $t+\Delta t$ - Particle at P' - $\overrightarrow{O P^{\prime}}=\overrightarrow{r^{\prime}}(t+\Delta t)$ - At time $t$, point $P$. - $\overrightarrow{PP'} \rightarrow$ Displacement vector.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Velocity And Acceleration
- $\operatorname{lim}_{\Delta t \rightarrow 0} \frac{\vec{r}(t+\Delta t)-\vec{r}(t)}{\Delta t}$ - $=\vec{v}(t) $ - $ \vec{V}_p(\text { at time t})$ = Derivative of position vector - Acceleration of point $P$ : - $\overrightarrow{a_p}= \operatorname{lim}_{\Delta t \rightarrow 0} \frac{{\overrightarrow{V_p}(t+\Delta t)-\overrightarrow{V_p}(t)}}{\Delta t}$.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Motion in a Straight Line
- Particle moves along a straight line. - Align ${x}-$ axis along the straight line.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Motion in a Straight Line
- Particle travels along $(x)$-axis or ${-x}$-axis.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Problem
- **Position:** - Location in space where the particle is at time t. - t= 0s Particle at O - t= 1s Particle at P - t= 2s particle at Q - t= 3s Particle at P
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Analysis
- Displacement $ \equiv \frac{\Delta x}{\Delta t}=\frac{x_2-x_1}{t_2-t_1}$ - $x_ 2>x_1 \rightarrow $ positive axis - $x_ 2< x _ 1 \rightarrow $ negative axis
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Displacement
- Displacement can be positive and negative. - Positive $\rightarrow$ if particle moves along ${x}$-axis. - Negative if paricle move against x axis. - Moving along $-x$ axis. - Displacement is a vector quantity. - In one dimensional motion, direction of displacement is given by the sign, is positive then it is along + x axis and if it is negative then it is along - x axis.
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Introduction To Kinematics Basic Mathematical Concepts L-2
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Thank You