Concise Physics Handbook

Formulas for Key Sections

Kinematics

a branch of mechanics that studies the motion of bodies without investigating the causes of that motion. It answers the question: how does a body move, not why.

1. Uniform Motion

Velocity and Coordinate:

Formulas for average velocity and coordinate in uniform motion

v=St; x=x0 ±v·t
What does this formula mean?

The formula describes the motion of a body at a constant velocity. v is the velocity, equal to the ratio of path S to the time t taken. Coordinate x changes uniformly, depending on the initial position x₀ and velocity v.

Displacement:

Formulas for body displacement in uniform motion

S=x-x0 =v·t
What does this formula mean?

The formula shows the distance traveled by a body in time t. This can be calculated as the difference between the final and initial coordinates (x − x₀), or as the product of constant velocity v and the time of motion. Only suitable for uniform motion.

2. Uniformly Accelerated Motion

Acceleration:

Formula for acceleration as the ratio of change in velocity to time interval

a= Δv Δt = v-v0 t
What does this formula mean?

Acceleration a shows how quickly the velocity of a body changes over a period of time. If the body accelerates or decelerates uniformly, then the change in velocity (Δv) is divided by the time interval (Δt), giving the acceleration in m/s².

Velocity:

Formula for velocity in uniformly accelerated motion

v=v0 ±a·t
What does this formula mean?

The formula reflects the change in velocity v of a body over time. The initial velocity v₀ increases (or decreases) by the amount of acceleration a, multiplied by time t. The ± sign depends on whether the body is accelerating or decelerating.

Coordinate:

Formula for coordinate in uniformly accelerated motion

x=x0 ±v0·t ±a·t22
What does this formula mean?

This formula determines the position x of a body at any given time when moving with constant acceleration. The terms describe: the initial coordinate x₀, the contribution from the initial velocity v₀·t, and the contribution from acceleration, proportional to the square of time. It is applicable in the absence of resistance and with constant acceleration.

3. Free Fall

Velocity in Fall:

Formula for body velocity in free fall or vertical motion

v=v0 ±g·t
What does this formula mean?

This formula describes the velocity of a body during free fall, starting with an initial velocity v₀, taking into account the acceleration due to gravity g and time t. The ± sign depends on the direction of motion: up or down.

Height:

Formula for height in vertical body motion with initial velocity

h=v0·t ± g·t2 2
What does this formula mean?

The formula describes how the height of a body changes during vertical motion. The first term is the contribution of the initial vertical velocity, the second is the influence of gravitational acceleration. The ± sign depends on the direction of motion: upwards (decreasing height over time) or downwards (increasing height relative to the start).

Without Time:

Formula for body velocity in vertical motion without using time

v2= v02 ±2g·h
What does this formula mean?

The formula allows calculating the velocity v of a body without explicitly stating time — through its initial velocity v₀ and displacement height h. This is convenient when the fall height is known but the time is not. The ± sign depends on the direction: acceleration towards the ground or deceleration when rising.

4. Projectile Motion

Velocity Projections:

Formulas for horizontal and vertical velocity projections in projectile motion

v0x=v0cosα; v0y=v0sinα
What does this formula mean?

The initial velocity v₀ of a body thrown at an angle α is broken down into two components: horizontal v₀ₓ and vertical v₀ᵧ. This allows treating the motion independently along the X and Y axes, simplifying calculations of trajectory and flight time.

Horizontal Displacement: 

Formula for horizontal displacement of a body in projectile motion

x=v0x·t
What does this formula mean?

The formula describes the horizontal distance traveled during the body's motion. Since there is no acceleration along the X-axis, the motion is uniform, and the path is calculated using the classical formula — velocity multiplied by time.

Vertical Displacement:

Formula for vertical displacement of a body in projectile motion

y=v0y·t mo - g·t2 2
What does this formula mean?

This formula determines the body's position at any given time after launch. The first part is the inertial ascent due to initial momentum, the second is the descent due to gravity. Together, they describe the parabolic trajectory.

Time to Climb:

Formula for the time it takes for a body to reach maximum height in projectile motion

tmax= v0y g
What does this formula mean?

This formula shows how long a body will ascend until it reaches its maximum height. At this point, the vertical velocity becomes zero. The greater the initial vertical velocity, the longer the ascent.

Maximum Height:

Formula for the maximum height of a body launched at an angle to the horizon

Hmax= v0y2 2g = v02 sin2α 2g
What does this formula mean?

The maximum flight height is reached when the vertical velocity becomes zero. It depends on the initial vertical velocity and the acceleration due to gravity. The second version of the formula shows the dependence on the total initial momentum and the launch angle.

Range:

Formula for the range of a body launched at an angle to the horizon

L= v02 sin(2α) g
What does this formula mean?

This formula shows how far from the launch point the body will land. It depends on the initial velocity, launch angle, and gravitational force. The sine of twice the angle determines the optimal angle for maximum range — 45°, all else being equal.

5. Circular Motion

Frequency and Arc:

Formulas for oscillation frequency and arc length of a circle

ν=1T; S=Δφ·R
What does this formula mean?

Frequency ν is the number of revolutions per second, inversely proportional to the period T of one revolution. The arc formula S shows the path traveled by a rotating body as the product of the angle of rotation Δφ (in radians) and the radius of the circle R.

Angular Displacement:

Formula for angular displacement of a body in circular motion

Δφ= φ2- φ1
What does this formula mean?

Angular displacement Δφ shows the angle a body has rotated during circular motion. It is the difference between the final and initial angle values, measured in radians.

Angular Velocity:

Formulas for angular velocity in rotational body motion

ω= Δφt= 2πT= 2πν
What does this formula mean?

Angular velocity ω measures how fast a body rotates around an axis. It shows how many radians the body turns per unit of time. All three forms are equivalent and reveal the relationship between angular displacement, period, and rotational frequency.

Linear Velocity:

Formulas for linear velocity in translational and rotational motion

v= St= Δφ·Rt= ω·R
What does this formula mean?

Linear velocity v shows how fast a body moves along a circular trajectory. It can be expressed through distance over time, through angular displacement, or directly through angular velocity and radius. The formula combines rotational and translational motions.

Centripetal Acceleration:

Formulas for centripetal acceleration in circular motion

ac= v2R= ω2·R
What does this formula mean?

Centripetal acceleration is directed towards the center of rotation and is necessary to maintain motion along a circular path. It depends on the square of the velocity (linear or angular) and is inversely proportional to the radius.

Angular Acceleration:

Formula for angular acceleration as the ratio of change in angular velocity to time interval

ε= ΔωΔt
What does this formula mean?

Angular acceleration ε describes how quickly the angular velocity of a rotating body changes. It is analogous to linear acceleration, but in the context of rotational motion — and depends on the change in angular velocity over a specific time interval.

Tangential Acceleration:

Formula for tangential acceleration in rotational body motion

aτ=ε·R
What does this formula mean?

Tangential acceleration aτ is responsible for the change in linear velocity of a body moving in a circle. It occurs when the angular velocity changes over time (there is angular acceleration ε). This acceleration acts along the tangent to the trajectory.