WEBVTT
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A cube is resting on a flat surface.
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The cube exerts a downward force of 92 newtons on the surface.
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The pressure on the surface is 23 newtons per metre squared.
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Calculate the side length of the cube.
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π is equal to πΉ over π΄, where π is pressure, πΉ is force, and π΄ is area.
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To calculate pressure, you need to know the force as shown.
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But you also need to know the surface area over which the force is spread.
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We are given that the force is 92 newtons and the pressure is 23 newtons per metre squared.
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We can therefore substitute this into the formula for pressure to help us calculate the surface area over which the force is spread.
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That gives us 23 is equal to 92 over π΄.
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To solve this for π΄, we first need to multiply both sides of our equation by π΄.
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That gives us 23π΄ is equal to 92.
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Next, we will divide both sides of our equation by 23, giving us that π΄ is equal to 92 over 23.
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We can write out the first four numbers of the 23 times tables to spot that 92 divided by 23 is four.
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The surface area over which the force is spread is then four metres squared.
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However, the question asked us to find the side length of the cube.
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We know that each face on a cube is a square.
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We calculated that the area of this square should be four metres squared.
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Letβs call the dimensions of our square π₯.
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And since the area of a square is found by multiplying its base by its height, we get π₯ multiplied by π₯, or π₯ squared, is equal to four.
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To solve this equation, we can find the square root of both sides.
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And the square root of four is just two.
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This means then that the side length of our cube must be two metres.