1.4. Total Resistance Calculation

So, let us convert the vehicle weight into tons, because your rolling resistance is commonly expressed as kg per ton. So, let us convert the weight of the machine into tons you know that the gross weight of the machine is given as 50,000 kg. So, 1000 kg = 1 ton, so divided you will get the gross weight of the machine as 50 tons.

In this chunk, we learn how to convert the weight of a vehicle from kilograms to tons. Since rolling resistance is measured in kilograms per ton, the conversion is necessary for accurate calculations. We take the gross weight of the machine, 50,000 kg, and divide this by 1,000 (the number of kilograms in one ton) to find that it weighs 50 tons.

Imagine you have a box of apples that weighs 2,000 grams. If you want to know how many kilograms that is, you would divide by 1,000. So, just like those apples, the machine's weight is converted from kilograms to tons to make it easier to compute other factors.

Now the rolling resistance you need to calculate for this particular haul route it is given as 28 kg per ton. So, you multiply the gross weight of the machine by the rolling resistance value. So, gross weight is 50 tons multiplied by the rolling resistance is 28 kg per ton for that particular haul route. So, now we are going to calculate for your particular vehicle what is the total rolling resistance? That is nothing but 1400 kg, so 1400 kg is your rolling resistance.

Here, we calculate the rolling resistance using the formula: Rolling Resistance = Gross Weight × Rolling Resistance Value. The gross weight is 50 tons and the rolling resistance value is 28 kg per ton. Thus, we calculate 50 tons × 28 kg/ton = 1400 kg, which means the rolling resistance opposing the machine's movement is 1400 kg.

Think about riding a bicycle. If your bike weighs 10 kg, and the tire's rolling resistance is like a soft surface that makes it harder to pedal. Just like multiplying the weight of your bike by how much harder it is to ride makes total sense when calculating the effort needed.

Now we need to find the penetration resistance. It is given to you in the problem that the tyre is sinking to the depth of 6 centimeters into the surface. So, you know that for each centimeter of penetration the amount of effort needed is 6 kg per ton per centimeter you know that. So, you multiply that by how much is the depth of penetration? It is nothing but 6 centimeters, and what is the gross weight of the machine? It is nothing but 50 tons. So, that gives you the penetration resistance as 1800 kg.

In this chunk, we determine the penetration resistance, which occurs when the tire sinks into the surface, affecting the machine's movement. The depth of penetration is 6 cm, and for each cm, it requires 6 kg of effort per ton. So we calculate: Penetration Resistance = Depth × 6 kg/ton × Gross Weight = 6 cm × 6 kg/cm × 50 tons = 1800 kg.

Imagine pushing a toy car into soft sand. The deeper the car sinks, the harder you have to push to get it out. Similarly, the machine's tires sinking into the ground creates resistance that we need to calculate.

Now we can find the total resistance, that is nothing but add your rolling resistance and the penetration resistance. It is nothing but your 1400 kg + 1800 kg, so that gives me the answer as 3200 kg is the total resistance.

Total resistance is calculated by combining rolling resistance and penetration resistance. By adding them together (1400 kg + 1800 kg), we find that the total resistance the machine faces is 3200 kg. This total resistance impacts the tractive effort required to move the machine.

Think of carrying two heavy bags. If one bag weighs 14 kg and the other weighs 18 kg, you need to consider both bags together to understand how heavy they are as a whole. Similarly, total resistance combines both types of resistance to see what the machine must overcome.

So, I need tractive effort of at least 3200 kg to overcome this resistance in a project site. So, the total tractive effort needed to overcome this resistance is 3200 kg. So, select the machine accordingly, that is the purpose of estimating all this resistance, so that we can know what is the required power for your machine? Select a machine that can generate enough power to overcome this resistance.

The total tractive effort needed to overcome the total resistance (3200 kg) is crucial for selecting the right machine for the task. The machine must be able to produce enough power to manage this resistance efficiently, ensuring it can perform the required work.

Imagine you need to haul a load of heavy bricks. You wouldn't choose a small truck if you know the load is exceptionally heavy. Similarly, estimating the resistance helps choose the right machinery capable of performing the task effectively.

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