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9 (a) The magnitude and direction of a force can be represented by a vector - Edexcel - GCSE Physics - Question 9 - 2020 - Paper 1
Question 9
9 (a) The magnitude and direction of a force can be represented by a vector. Figure 22 shows the forces acting on four identical trolleys. The arrows show the magni... show full transcript
Worked Solution & Example Answer:9 (a) The magnitude and direction of a force can be represented by a vector - Edexcel - GCSE Physics - Question 9 - 2020 - Paper 1
Step 1
Draw a vector diagram and use it to determine the resultant force that the boats exert on the ship.
Answer
To solve this part, we first start by understanding that the two boats exert forces at right angles to each other, each with a tension (T) of 20 kN. We can illustrate this using a right triangle.
Using the Pythagorean theorem to find the resultant force (R):
Substituting the values:
R \approx 28.28 kN$$ Thus, the resultant force that the boats exert on the ship is approximately 28.3 kN.Step 2
Explain how the forces keep the wooden block moving across the table at a constant horizontal velocity.
Answer
For the wooden block to move across the table at a constant horizontal velocity, the following forces are at play:
Horizontal Forces:
- Tension in the String: The tension from the weight pulling on one end of the string acts horizontally and is one of the key forces involved.
- Friction Between the Block and Table: Friction acts in the opposite direction to the motion, helping to balance forces.
- Balanced Forces: Since the block is moving at a constant velocity, the horizontal forces must be equal (net force is zero). Therefore, the upward tension from the string is countered by friction, keeping the net force at zero and maintaining constant motion.
Vertical Forces:
- Normal Reaction Force: Every solid surface generates a normal force perpendicular to the contact surface which counteracts the weight of the block.
- Weight of the Block: The downward gravitational force keeps pushing the block onto the table.
In summary, all forces on the wooden block balance out, resulting in no net force, hence the constant horizontal velocity.