Forces in Action | OCR A-Level Physics A (H556)
Forces in Action
- 64 questions
- 5 subtopics
- Module 3: Forces and motion
- Paper 1 and Paper 3
Newton's second law in use, drag and terminal velocity, moments and equilibrium, and the pressure and upthrust a fluid exerts..
It covers newton's second law and weight, drag and the factors affecting it, terminal velocity, moments, couples and equilibrium and density, pressure and upthrust.
Sample questions from Forces in Action
Answer each one closed book first, then open the answer.
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Newton's second law and weight
What is the weight of an object?
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The weight of an object is the gravitational force acting on it. -
Newton's second law and weight
What is friction?
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Friction is the resistive force that opposes the relative motion or tendency of motion between two surfaces in contact. -
Drag and the factors affecting it
How does the cross-sectional area of an object affect the drag force when travelling through air?
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A larger cross-sectional area results in a greater drag force. -
Drag and the factors affecting it
What happens to the drag force on a falling object as its speed increases?
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The drag force increases with speed. -
Terminal velocity
How are distance intervals used when measuring terminal velocity in a viscous liquid?
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Distance intervals are marked on the container so the ball-bearing's position can be tracked as it falls. -
Terminal velocity
In an experiment to determine terminal velocity in air using paper cones, how is the cone released?
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The cone is released from a height and allowed to fall freely. -
Moments, couples and equilibrium
Write the equation for the torque of a couple.
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Torque = Fd, where F is one of the forces and d is the perpendicular distance between the lines of action. -
Moments, couples and equilibrium
How is the centre of gravity identified from the marked lines on an irregular lamina?
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The centre of gravity is located at the intersection of the vertical lines marked from different suspension points.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Newton's second law and weight | Recall questions on Newton's second law and F = ma, the newton, weight and its calculation, tension, normal contact force and friction, and analysing motion under a constant force in one and two dimensions. | 12 |
| Drag and the factors affecting it | Recall questions on drag and how speed, cross-sectional area, shape and fluid density affect it, and how drag changes the net force and acceleration of a falling object. | 8 |
| Terminal velocity | Recall questions on defining terminal velocity, the initial acceleration of a falling object, and determining terminal velocity experimentally in a viscous liquid and with paper cones in air. | 11 |
| Moments, couples and equilibrium | Recall questions on free-body diagrams, moments and the principle of moments, couples and torque, centre of mass and centre of gravity, finding the centre of gravity of a lamina, and the conditions for equilibrium. | 19 |
| Density, pressure and upthrust | Recall questions on density and pressure with their calculations, pressure at a depth p = hρg, why pressure increases with depth, how the pressure difference produces upthrust, and Archimedes' principle. | 14 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
OCR A-Level Physics A Active Recall Guide
Every topic, not just this one. 1,862 questions with their answers.