Find the tracrive force

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In summary, when calculating the tractive force exerted by an engine, it is important to take into account all external forces, including the constant resistance to motion. In this problem, the tractive force was found to be 9250N, considering the constant resistance of 250N and a car with a mass of 900kg accelerating from rest to a speed of 20ms^-1 in a distance of 80m.
  • #1
looi76
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Homework Statement


A car pf mass 900kg accelerates from rest to a speed of 20 ms^-1 whilst moving 80m along a horizontal road. Find the tractive force (i.e. the driving force) exerted by the engine, assuming that it is constant and that there is a constant resistance to motion of 250N.

Homework Equations



The Attempt at a Solution


m = 900kg, u=0ms^-1 , v=20ms^-1, s = 80m
acceleration = (20-0)/2 = 10ms^-2
force = ma = 900*10 = 9000N
workdone = 7.2*10^5J

What about the constant resistance to motion of 250?
 
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  • #2
How does that affect the calculation?

Your solution is correct in calculating the tractive force exerted by the engine, assuming there is no other external force acting on the car. However, the constant resistance to motion of 250N should be taken into account in the calculation.

To incorporate this resistance force, we can use the following equation:

Fnet = ma = Fengine - Fresistance

Where Fnet is the net force acting on the car, Fengine is the tractive force exerted by the engine, and Fresistance is the resistance force.

Rearranging the equation, we get:

Fengine = ma + Fresistance

Substituting the values from the given information, we get:

Fengine = (900kg)(10ms^-2) + 250N = 9250N

Therefore, the tractive force exerted by the engine is 9250N. This means that the engine has to overcome a resistance force of 250N in order to accelerate the car from rest to a speed of 20ms^-1 in a distance of 80m.

In conclusion, it is important to take into account all external forces acting on an object when calculating the net force and the tractive force exerted by an engine. This ensures a more accurate and comprehensive solution.
 
  • #3


To find the tractive force, we need to consider the net force acting on the car. In this case, the net force is equal to the driving force (tractive force) minus the resistance force.

Therefore, the tractive force can be calculated as:

Ft = m*a + Fr

Where Ft is the tractive force, m is the mass of the car, a is the acceleration, and Fr is the resistance force.

Substituting the given values, we get:

Ft = (900kg)*(10ms^-2) + 250N
Ft = 9250N

Therefore, the tractive force exerted by the engine is 9250N. This is the force that is responsible for accelerating the car from rest to a speed of 20ms^-1.
 

What is the definition of "Find the tractive force"?

"Find the tractive force" refers to calculating the force needed to overcome the friction and move an object along a surface.

How is tractive force calculated?

Tractive force can be calculated by multiplying the coefficient of friction between the object and the surface by the weight of the object.

What factors can affect the tractive force?

The tractive force can be affected by the weight and surface area of the object, as well as the type of surface and the coefficient of friction.

Why is tractive force important to consider?

Tractive force is important to consider when designing machinery, vehicles, and other objects that need to be moved along a surface. It helps determine the amount of force needed and can impact the efficiency and effectiveness of the object.

Can tractive force be increased?

Yes, tractive force can be increased by either increasing the weight of the object or by decreasing the coefficient of friction through the use of lubricants or smoother surfaces.

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