3.4. Calculating Usable Force

Try these first

1. 1.

   Calculate the rolling resistance for a truck weighing 20 tons with a rolling resistance of 50 kg/ton.

   Hint

   Multiply the weight (in tons) by the rolling resistance.

2. 2.

   What is the penetration resistance for a vehicle that sinks 5 cm with 6 kg/ton resistance?

   Hint

   Use the formula: Penetration Resistance = Depth (cm) × Resistance (kg/ton) × Weight (tons).

3. 3.

   What is the formula for calculating total rolling resistance?

   • Total Resistance = Rolling Resistance + Penetration Resistance
   • Total Resistance = Weight × Rolling Resistance
   • Total Resistance = Weight ÷ Rolling Resistance

   Hint

   Think about what we multiply for finding rolling resistance!

4. 4.

   True or False: Grade resistance increases as the slope steepness increases.

   • True
   • False

   Hint

   Grade resistance relates to how steep a slope is.

5. 5.

   A construction vehicle has a gross weight of 20 tons, a rolling resistance of 50 kg/ton, and encounters a slope of 5%. Calculate the total resistance faced and determine the usable power if the machine's maximum power is rated at 6000 kg.

   Hint

   Calculate each resistance first before determining usable power.

6. 6.

   A truck weighs 12 tons with a rolling resistance of 30 kg/ton and is lowering down a slope of 7%. Calculate the grade resistance and determine how much usable power remains from a maximum power of 7000 kg.

   Hint

   Calculate to understand how resisting forces impact usable work.