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2 bodies on an incline plane

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Two blocks,  A & B,  rest on a slope at an angle of incline θ. 

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The mass and coefficents of friction between the crates and the plane are:

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mass (kg)Coefficient of Friction (μ)
Crate A{mass_crate_A}{co_eff_A}
Crate B{mass_crate_B}{co_eff_B}
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Worked answers to follow exam

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Gravitational Constant

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Mass of Crate B (kg)

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N

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N

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Calculate (to within 1 decimal place) the angle θ when Crate A begins to slide.

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Free body diagram of Crate A:

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\"Free

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Calculate the weight (N) of the crate:

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Which of the following expressions is true?

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WA(parallel) = WAsin(θ)

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WA(parallel) = WAcos(θ)

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Which of the following is the correct expression for the frictional force acting on the crate?

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FA(Max) = μANA = μA x WA(Normal) = μAWAsin (θ)

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FA(Max) = μANA = μA x WA(Normal) = μAWAcos (θ)

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FA(Max) = μANA = μA x WA(Normal) = μAWAtan (θ)

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For the crate to be slipping, which of the following conditions must be true?

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WA(parallel) > FA(Max)

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WA(parallel) = FA(Max)

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Use the standard trigonometric expression sin(θ)/cos(θ) = tan(θ) and the expressions above to calculate the angle that the box begins to slide.

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Calculate (to within 1 decimal place) the angle θ when Crate B begins to slide.

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Which of the following expressions is true?

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μB = WBsin(θ) / WBcos (θ)= tan(θ)

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μB = WBcos(θ) / WBsin (θ)= tan(θ)

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μB = WBsin(θ) / WBcos (θ)= tan-1(θ)

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Use the standard trigonometric expression sin(θ)/cos(θ) = tan(θ) and the expressions above to calculate the angle that the box begins to slide.

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If the 2 masses are connected at points C & D by a cable (as shown). 

\n

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Calculate the angle (to within 1 decimal place) the two joined crates begin to slide.

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Free Body Diagram:

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For the 2 crates to begin to slide, which of the following expressions is true?

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WA(parallel) + WB(parallel) ≥ FA + FB

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WA(parallel) + FA ≥ WB(parallel) + FB

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WA(parallel) - WB(parallel) ≥ FA - FB

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What is the total weight of the system?

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If the boxes were on a level surface, what would be the total frictional force between the boxes and the surface?

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Use the standard trigonometric expression sin(θ)/cos(θ) = tan(θ) and the expressions above to calculate the angle that both the boxes begin to slide.

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A message

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