Physics Research Archive

The Evidence

Four core physical questions explored through classical mechanics, energy transfer, elasticity, and momentum conservation.

Overview

Foundational Physics

This archive investigates slope angle and acceleration, wind-turbine blade count, spring stiffness in series versus parallel arrangements, and momentum transfer during collisions between moving and stationary objects. All models and equations reflect established physical principles.

Investigation 01

Classical mechanics

Does changing an angle affect acceleration?

Research question: If an object slides down a ramp, does making the ramp steeper change how quickly it speeds up?

For an ideal object sliding down a straight incline without friction, the acceleration along the slope depends on the component of gravity parallel to the surface. If the angle is measured from the horizontal, a steeper ramp gives a larger component of gravity along the ramp.

a = g sin(θ)

Here, a is acceleration along the slope, g is gravitational acceleration, and θ is the incline angle above horizontal. With kinetic friction, a simple model for downward sliding is a = g(sin θ − μₖ cos θ), where μₖ is the coefficient of kinetic friction, provided the object is sliding down the ramp.

Finding

Angle directly affects acceleration. To test it experimentally, release the same trolley from the same starting point at several measured ramp angles, keeping the surface and trolley unchanged, and repeat each trial. Record the angle and acceleration, and compare averages. Friction, rolling resistance, and timing uncertainty should be accounted for in calculations.

Investigation 02

Wind energy

Do more turbine blades generate more power?

Research question: If blades catch the wind, would adding more blades always increase the electricity generated?

Not automatically. Blade count influences rotor solidity, torque, drag, rotational speed, mass, and cost. Three-bladed horizontal-axis turbines are common because they offer an optimal engineering balance; blade count alone does not determine output. Blade profile, rotor diameter, wind speed, generator type, and control system also dictate overall efficiency.

P_wind = ½ ρ A v³

This equation gives the power available in the wind: ρ is air density, A is the rotor’s swept area, and v is wind speed. A turbine captures only a fraction of this power, and electrical losses reduce the delivered output further.

Finding

More blades do not guarantee more electrical power. For a controlled model-turbine experiment, hold wind speed, rotor diameter, blade material, blade pitch, and electrical load constant. Change the blade count, measure voltage and current under the load, and estimate output using P = VI.

Investigation 03

Elasticity

How does spring constant k change in series and parallel?

Research question: Can the same springs act softer or stiffer simply by changing how they are connected?

Hooke’s law for an ideal spring within its elastic limit is F = kx, where F is the magnitude of the applied force, x is extension or compression, and k is stiffness in newtons per metre (N/m). For springs in series, each spring carries the same force and their extensions add. For springs in parallel, they undergo the same extension and their forces add.

Series · end-to-end

1/kₑq = 1/k₁ + 1/k₂

The combined system is less stiff than either spring alone.

Parallel · side-by-side

kₑq = k₁ + k₂

The combined system is stiffer than either spring alone.

For two identical springs, each with k = 100 N/m, the effective stiffness is 50 N/m in series and 200 N/m in parallel. The individual material stiffness of each spring remains unchanged; only the effective stiffness of the arrangement changes.

Finding

Hang a known mass from a single spring, two springs in series, and two in parallel. Measure extension x and calculate stiffness using k = F/x = mg/x. Ensure loads remain within the elastic limit and measure relative to the unloaded length.

Investigation 04

Collision dynamics

How is momentum transferred between moving and stationary objects?

Research question: When a moving object strikes a stationary one, how is motion redistributed across the collision?

In an isolated system, total linear momentum is conserved in all collisions. When a moving object of mass m₁ traveling at initial velocity v₁ᵢ collides with a stationary object of mass m₂ (v₂ᵢ = 0), the moving object exerts an impact force over a brief duration Δt, imparting an impulse that transfers momentum to the stationary target.

m₁ v₁ᵢ = m₁ v₁_f + m₂ v₂_f

The distribution of final velocities depends on whether the collision is elastic (where kinetic energy is conserved) or inelastic (where objects couple together or deform). In a perfectly elastic collision between equal masses, the moving object stops completely, transferring all its momentum to the target object.

Finding

Momentum is transferred from the incident object to the stationary one. To verify this, collide two dynamics carts on a low-friction track—one in motion and one at rest. Use photogates to measure initial and final velocities, and compare total momentum before and after impact across elastic and inelastic conditions.