8.3. Gravity Resistance

Try these first

1. 1.

   Define rolling resistance.

   Hint

   Think about how tires interact with different surfaces.

2. 2.

   What factor greatly reduces rolling resistance on a hard surface?

   Hint

   Consider what keeps tires from sinking or dragging.

3. 3.

   What is rolling resistance driven by?

   • Weight of machine
   • Type of fuel
   • Speed of machine

   Hint

   Think about what happens when machines roll on softer surfaces.

4. 4.

   True or False: Higher tire pressure on a soft surface reduces rolling resistance.

   • True
   • False

   Hint

   Consider how tires behave differently on hard vs. soft surfaces.

5. 5.

   A construction vehicle with a gross weight of 40,000 kg is moving on a gravel road with a rolling resistance of 90 kg per ton. If the vehicle sinks 4 cm into the ground, calculate the total tractive effort required.

   Hint

   Break down the rolling resistance into weight and penetration force.

6. 6.

   Discuss how machinery would operate differently on a wet, muddy road compared to a dry, firm surface. What implications does this have for estimated power requirements?

   Hint

   Consider factors like rolling and penetration resistance in context.