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6 (a) The magnitude and direction of a force can be represented by a vector - Edexcel - GCSE Physics Combined Science - Question 6 - 2020 - Paper 1
Question 6
6 (a) The magnitude and direction of a force can be represented by a vector. Figure 13 shows the forces acting on four identical trolleys. The arrows show the magnit... show full transcript
Worked Solution & Example Answer:6 (a) The magnitude and direction of a force can be represented by a vector - Edexcel - GCSE Physics Combined Science - Question 6 - 2020 - Paper 1
Step 1
(b) Draw a vector diagram and use it to determine the resultant force that the boats exert on the ship.
Answer
To determine the resultant force that the boats exert on the ship, we must first represent the tension forces in each rope:
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Draw the Tension Vectors:
- Using a right triangle, draw one tension vector (T) vertically and the other tension vector (T) horizontally since they are at right angles to each other.
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Calculate Resultant Force:
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Each tension vector has a magnitude of 20 kN.
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The resultant force (R) can be calculated using the Pythagorean theorem:
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Label the Vector Diagram:
- Clearly label the magnitudes of each tension force and the resultant force on the diagram.
The magnitude of the resultant force that the boats exert on the ship is approximately 28.3 kN.
Step 2
(c) Explain how the forces keep the wooden block moving across the table at a constant horizontal velocity.
Answer
To explain how the forces keep the wooden block moving across the table at a constant horizontal velocity, we must consider both horizontal and vertical forces:
Horizontal Forces:
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Tension in the String:
- The tension in the string pulling the block is one of the horizontal forces acting on it.
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Friction:
- There is friction between the table and the wooden block. This friction opposes the motion of the block.
- The force due to friction acts in the opposite direction of the tension.
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Balanced Forces:
- For the block to move at a constant velocity, the forces must be balanced:
- The tension provided by the string equals the force due to friction.
- Hence,
- For the block to move at a constant velocity, the forces must be balanced:
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No Resultant Force:
- With balanced forces, the net force on the block is zero, meaning it continues to move at a constant horizontal velocity.
Vertical Forces:
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Normal Reaction:
- The normal force (reaction force) acts upwards between the table and the wooden block, balancing the weight acting downwards.
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Weight of the Block:
- The weight of the block (force of gravity) acts downwards.
- Both the normal force and weight are equal and opposite, which results in no vertical acceleration.
In summary, the balance of horizontal forces ensures constant horizontal motion while vertical forces maintain equilibrium, effectively allowing the block to maintain a constant horizontal velocity.