NSC Technical Sciences Different kinds of forces: Tom is pushing and Zane is pulli

Tom is pushing and Zane is pulling a trolley, loaded with crushed stone, over a rough surface on a construction site - NSC Technical Sciences - Question 3 - 2020 - Paper 1

Question 3

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Tom is pushing and Zane is pulling a trolley, loaded with crushed stone, over a rough surface on a construction site. The mass of the trolley and its contents is 350... show full transcript

Worked Solution & Example Answer:Tom is pushing and Zane is pulling a trolley, loaded with crushed stone, over a rough surface on a construction site - NSC Technical Sciences - Question 3 - 2020 - Paper 1

Step 1

Define tension force, and give an example of such a force in the diagram above.

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Answer

Tension force is a pulling force that is transmitted through a string or rope. In this scenario, the force applied by Zane ( F_{Zane} = 160 ext{ N}) is an example of tension force acting on the trolley.

Step 2

How will the frictional force on the trolley be affected by Zane's applied force? Write only INCREASES, DECREASES or REMAINS CONSTANT.

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Answer

The frictional force on the trolley will DECREASE due to Zane's applied force as it contributes to lifting the trolley off the surface.

Step 3

Draw a free-body diagram of ALL the forces acting on the trolley and its contents.

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Answer

The free-body diagram includes:

The normal force ( F_{N} ) acting upwards.
The gravitational force ( F_{g} ) acting downwards equal to the weight of the trolley (mass imes gravity).
The tension force ( F_{Zane} ) pulling at an angle of 65°.
The applied force by Tom ( F_{Tom} ) which is pushing horizontally.
The frictional force ( F_{f} ) acting opposite to the direction of motion.

Step 4

If the net force acting on the trolley and its contents is 205 N, calculate the coefficient of kinetic friction (μk) between the surface and the trolley.

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Answer

Using Newton's second law:

$F_{net} = F_{Tom} + F_{Zane} imes ext{cos}(65°) - f_{k}$

Letting east be positive, we have:

$205 = 200 + 160 imes ext{cos}(65°) - f_{k}$

Calculating the forces:

$F_{Zane} imes ext{cos}(65°) = 160 imes 0.4226 = 67.62 ext{ N}$

Thus:

$205 = 200 + 67.62 - f_{k}$

Now solving for f_{k} :

$f_{k} = 200 + 67.62 - 205 = 62.62 ext{ N}$

Finally, the coefficient of kinetic friction (μk) is given by:

u_{k} = rac{f_{k}}{F_{N}}$$ Calculating the normal force: $$F_{N} = m imes g = 350 imes 9.81 = 3433.5 ext{ N}$$ Thus: $$μ_{k} = rac{62.62}{3433.5} ightarrow μ_{k} ext{ is approximately } 0.0182$$.

Tom is pushing and Zane is pulling a trolley, loaded with crushed stone, over a rough surface on a construction site - NSC Technical Sciences - Question 3 - 2020 - Paper 1

Worked Solution & Example Answer:Tom is pushing and Zane is pulling a trolley, loaded with crushed stone, over a rough surface on a construction site - NSC Technical Sciences - Question 3 - 2020 - Paper 1

Define tension force, and give an example of such a force in the diagram above.

How will the frictional force on the trolley be affected by Zane's applied force? Write only INCREASES, DECREASES or REMAINS CONSTANT.

Draw a free-body diagram of ALL the forces acting on the trolley and its contents.

If the net force acting on the trolley and its contents is 205 N, calculate the coefficient of kinetic friction (μk) between the surface and the trolley.

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