Newton's First Law (Oxford AQA IGCSE Physics)

Revision Note

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Expertise

Physics

If the resultant force acting on an object is zero:
- A moving object will continue to move at the same velocity
- A stationary object will remain at rest
This is Newton's first law of motion
You may also see it written as:

Objects will remain at rest, or move with a constant velocity unless acted on by a resultant force

There is zero resultant force acting on objects when the forces acting on the objects are balanced

A car travels in a straight line at a constant velocity.

Determine the magnitude of the frictional force acting on the car.

Answer:

Step 1: Recall Newton's first law of motion

Newton's first law of motion states that objects will remain at rest, or move with a constant velocity unless acted on by a resultant force

Step 2: Relate Newton's first law to the scenario

Since the car is moving at a constant velocity, there is no resultant force acting
This means the driving and frictional forces are balanced

Step 3: State the value of the frictional force

Frictional force = driving force

Frictional force = 3 kN

to absolutely everything:

the (exam) results speak for themselves:

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