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Edexcel IGCSE Physics 復(fù)習(xí)筆記 1.3.2 Forces & Momentum

Category: IGCSE課程, 國際課程, 教材筆記, 福利干貨 Date: 2022年7月18日下午4:10

Edexcel IGCSE Physics 復(fù)習(xí)筆記 1.3.2 Forces & Momentum

Forces & Momentum

When a force acts on an object that is moving, or able to move, the object will accelerate (or decelerate)
- This causes a?change in momentum
More specifically, the force is the?rate of change in momentum

3.1.1.4-Force-and-momentum-equation

Δt is the?change?in time, or the time taken for the force to change
Where the change in momentum is defined as

Final momentum – Initial momentum

Force and momentum are?vectors?so they can be either positive or negative values

Deriving the Force & Momentum Equation

The force and momentum equation can be derived from Newton's Second law and the definition of acceleration

5.9.4-Force-Momentum-Derivation

Worked Example

A tennis ball hits a racket with a change in momentum of 0.5 kg m/s.For the different contact times, which tennis racket experiences more force from the tennis ball?

WE-Tennis-ball-contact-time-answer-image

Exam Tip

Maths Tip:?Remember ‘rate of change’ describes how one variable changes with respect to anotherIn maths, how fast something changes with?time?is represented as dividing by?Δt?(e.g. acceleration is the rate of change in velocity)More specifically,?Δt?is used for finite and quantifiable changes such as the difference in time between two events WE-Tennis-ball-contact-time-content-part