# AP Inter 1st Year Physics Notes Chapter 3 Motion in a Straight Line

Students can go through AP Inter 1st Year Physics Notes 3rd Lesson Motion in a Straight Line will help students in revising the entire concepts quickly.

## AP Inter 1st Year Physics Notes 3rd Lesson Motion in a Straight Line

→ Path length is defined as the total length of the path traversed by an object.

→ Displacement is the change in position; ∆x = x2 – x1

→ Average velocity is the displacement divided by the time interval in which the displacement occurs. υ = $$\frac{\mathrm{dx}}{\mathrm{dt}}$$

→ Instantaneous velocity is defined’as the limit of the average velocity as the time interval At becomes infinitesimany small.

→ Average acceleration is the change in velocity divided by the time interval during which the change occurs, $$\overline{\mathrm{a}}=\frac{\Delta v}{\Delta \mathrm{t}}$$

→ Instantaneous acceleration is defined as the limit of the average acceleration as the time interval ∆t goes to zero.

→ Average speed is the ratio of total path length traversed and the corresponding time interval.

→ Equations of motion are
υ = υ0 + at
x = υ0t + $$\frac{1}{2}$$ at2
υ2 = υ20 + 2ax

→ Height of a tower is – h = ut – $$\frac{1}{2}$$ gt2

→ An object is released near the surface of the earth is accelerated under the influence of gravity. The object is said to be in free fall.

→ Acceleration due to gravity (g) is positive along +y direction and g is negative along – y direction

→ g value in downward motion is negative a = -g = -9.8 m/s2

1. v = 0 – gt = -9.8 t
2. y = 0 – $$\frac{1}{2}$$ gt2 = – 4.9 t2
3. υ2 = 0 – 2 gy = -19.6y

→ Relative velocity is the velocity one body w.r.to velocity of another body.

→ Relative velocity of A w.r.to B = $$\left|\vec{V}_A-\vec{V}_R\right|$$

→ Relative velocity of B w.r.to A = $$\left|\vec{V}_B-\vec{V}_A\right|$$

→ Dimensional formula of velocity = [LT-1].

→ Dimensional formula of acceleration = [LT-2].