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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 ma... 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, we begin by drawing a vector diagram representing the tensions in the ropes.
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Vector Representation: Since the ropes are at right angles to each other, we can represent one tension vector (T) horizontally and another vertically. Each has a magnitude of 20 kN.
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Applying Pythagoras' Theorem: The resultant force (R) can be calculated using the Pythagorean theorem:
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Conclusion: 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 maintain a constant horizontal velocity, several forces must be balanced. These include:
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Tension in the String: The tension (T) in the string, which pulls the block horizontally, acts in the forward direction.
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Friction Force: Friction opposes the motion of the block. The rough surface creates a frictional force that acts in the opposite direction to the tension.
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Equilibrium of Forces: For the block to move at a constant velocity, the net force must be zero. Therefore, the forward force due to tension must equal the backward force due to friction:
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Vertical Forces: In the vertical direction, the weight of the block acts downwards, and the normal reaction from the table acts upwards. These forces are also balanced, which allows the block to remain on the table without vertical acceleration.
In summary, as long as the tension in the string equals the frictional force, and the vertical forces are balanced, the wooden block will continue to move at a constant horizontal velocity.