Key Concepts in Acceleration and Sports Biomechanics

What is acceleration?

Acceleration is the rate of change of velocity with respect to time, indicating how quickly an object's speed is increasing or decreasing.

What does constant velocity mean for acceleration?

If velocity is constant, acceleration is zero because there is no change in speed or direction.

What are key measures in sports biomechanics?

Key measures include velocity, acceleration, force, momentum, mechanical energy, and angular velocity, which determine movement efficiency and performance.

What is the formula for acceleration?

The formula for acceleration is a = Δv / Δt (Change in velocity divided by change in time).

How does time affect a horizontally projected object's air time?

The object's time in the air is determined solely by vertical motion, meaning gravity dictates how long it stays airborne, regardless of horizontal velocity.

What happens to velocity when tossing an object in the air?

Velocity decreases on the way up (due to gravity opposing motion) and increases on the way down (due to gravity accelerating it), reaching zero at the highest point.

What is the SI unit for distance and displacement?

Meters (m) are the SI unit for both distance and displacement.

How does running downhill affect speed?

Running downhill increases speed due to gravitational acceleration aiding motion.

What influences the shape of a projectile's trajectory?

Initial velocity, angle of projection, air resistance, and gravity influence the shape of a projectile's trajectory.

What effect does acceleration have on velocity?

Acceleration changes velocity by either increasing or decreasing its magnitude.

What is the velocity of an object at the apex of its trajectory?

The vertical velocity is zero, but horizontal velocity remains constant (if air resistance is ignored).

What are the units of angular velocity?

Angular velocity is measured in radians per second (rad/s) or degrees per second (°/s).

What is an instantaneous center?

An instantaneous center is a point where the velocity of a rotating body is momentarily zero, often used in kinematic analysis.

What is a radian?

A radian is the angle subtended by an arc equal to the radius of a circle.

What is angular velocity?

Angular velocity is the rate at which an object rotates around an axis, measured in rad/s or degrees per second.

What are the units describing angular speed?

Angular speed is described in radians per second (rad/s), degrees per second (°/s), and revolutions per minute (RPM).

What affects radial acceleration?

Radial acceleration is affected by tangential velocity and the radius of circular motion.

What is the most commonly used unit of time for angular velocity calculations?

Seconds (s) are the most commonly used unit of time for angular velocity calculations.

What is the formula for force according to Newton's Second Law?

The formula for force is F = ma (Force equals mass times acceleration).

What are examples of Newton's Law of Inertia?

Examples include a moving car continuing to move unless brakes are applied and an object at rest staying at rest unless pushed.

What are examples of Newton's Law of Action-Reaction?

When a swimmer pushes water backward, the water pushes them forward.

What variables determine momentum?

Momentum is determined by mass and velocity, expressed as p = mv.

What is impact?

Impact is the collision between two bodies and the resulting force exerted.

What is impulse?

Impulse is the change in momentum caused by a force applied over a time interval.

What is potential energy?

Potential energy is stored energy due to an object's position, calculated as PE = mgh (mass × gravity × height).

What is kinetic energy?

Kinetic energy is the energy of motion, calculated as KE = 1/2 mv² (half mass times velocity squared).

What is mechanical power?

Mechanical power is the rate at which work is done, with examples including weightlifting, sprinting, and jumping.

What is the unit of mechanical energy?

The unit of mechanical energy is Joules (J).

What is the difference between kinetic and static friction?

Kinetic friction occurs when an object is moving, while static friction prevents motion.

What type of energy is strain energy?

Strain energy is elastic potential energy, stored in deformed materials.

What happens to momentum when an impulse acts on it?

Momentum changes based on the magnitude and direction of the impulse.

What are elastic and plastic impacts?

Elastic impacts conserve kinetic energy, while plastic impacts cause deformation and energy loss.

What is the coefficient of restitution?

The coefficient of restitution is a value between 0 and 1 measuring elasticity in collisions.

What is the formula for mechanical work?

The formula for mechanical work is W = Fd (Work equals force times displacement).

What are the formulas for mechanical power?

Mechanical power can be calculated as P = W/t (Power equals work divided by time) or P = Fv (Force times velocity).

What is the correct unit of mechanical power?

The correct unit of mechanical power is Watts (W).

When does friction occur?

Friction occurs whenever surfaces interact, such as running on pavement, tires gripping a road, or sliding a book across a desk.