Car pulls a trailer of weight

In summary, the conversation discusses the calculation of work done by a car in pulling a trailer of weight 2500 N for a distance of 8 km. The answer is determined to be 160,000 J. The concept of change in energy and its relation to the speed and mass of the trailer is also mentioned. The possibility of the 20 N force only overcoming air resistance is brought up for consideration.
  • #1
influx
164
2
EDIT: I JUST REALISED YOU CAN'T DO 1 WORD THREAD TITLES, SORRY ! WON'T DO IT AGAIN!

A car pulls a trailer of weight 2500 N with a force of 20 N for a distance of 8 km along
a horizontal road.

How much work is done by the car in pulling the trailer?
A 160 J
B 20 000 J
C 160 000 J
D 20 000 000 J

I know work done = force x displacement

so it should be 20 x 8000 = 160,000 J (so the answer is C)

But what I am confused about is surely the weight of the trailer will affect how much work the car does in pulling it? I mean for instance if the trailer was 5 N, shouldn't the work done be MUCH less .. BTW can you please try explain in simple terms since I am not that advanced at Physics as you guys.

Cheers :)
 
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  • #2
hi influx! :smile:
influx said:
A car pulls a trailer of weight 2500 N with a force of 20 N for a distance of 8 km along
a horizontal road.

How much work is done by the car in pulling the trailer?
…
… surely the weight of the trailer will affect how much work the car does in pulling it? I mean for instance if the trailer was 5 N, shouldn't the work done be MUCH less

work done = change in energy

if you applied the same force for the same distance, the two trailers' increased kinetic energy would be the same

but the heavier trailer's speed would have increased less :wink:
 
  • #3
tiny-tim said:
..

Hi :)

Oh! Never knew that! When you say change in energy, what exactly do you mean? And does the speed increase less because kinetic energy = 1/2(mv2) , so as the value for 'm' increases, the value of 'v' decreases?

Cheers
 
  • #4
influx said:
When you say change in energy, what exactly do you mean? And does the speed increase less because kinetic energy = 1/2(mv2) , so as the value for 'm' increases, the value of 'v' decreases?

if the speed goes from u to v, then the change in energy (on a horizontal road) is 1/2mv2 - 1/2mu2

if that is the same for two masses, the one with larger m must have smaller (v2 - u2)
 
  • #5
Who says that the 20N force is increasing the KE of the trailer, and not just overcoming air resistance?
 

1. How does the weight of a trailer impact a car's performance?

The weight of a trailer can significantly impact a car's performance in several ways. Firstly, it can affect the car's acceleration, as the added weight requires more power to move the vehicle. This can also result in decreased fuel efficiency. Secondly, the weight of the trailer can affect the car's braking distance, as it requires more force to stop a heavier load. Additionally, the weight distribution of the trailer can impact the car's handling and stability, especially when making turns or driving in windy conditions.

2. Can any car pull a trailer of any weight?

No, not all cars are capable of pulling trailers of any weight. The maximum weight that a car can safely tow is determined by its towing capacity, which is specified by the manufacturer. Exceeding this weight limit can cause strain on the car's engine, transmission, and brakes, potentially leading to mechanical issues and safety hazards.

3. How does the weight of a trailer affect a car's gas mileage?

The weight of a trailer can have a significant impact on a car's gas mileage. As mentioned before, a heavier load requires more power to move, which means the car will consume more fuel. This can result in a decrease in gas mileage, sometimes by as much as 25%. Additionally, the added weight can also increase air resistance, further decreasing the car's fuel efficiency.

4. What precautions should be taken when pulling a trailer of weight?

When pulling a trailer of weight, it is essential to take several precautions to ensure safe driving. Firstly, make sure that your car's towing capacity is not exceeded. Always distribute the weight evenly in the trailer and secure the load properly to prevent shifting while driving. It is also crucial to adjust your driving style, as the added weight can affect the car's handling and braking distance. Lastly, regularly check your car's tire pressure and brakes to ensure they are in good condition.

5. Can a car's towing capacity be increased?

No, a car's towing capacity cannot be increased beyond what is specified by the manufacturer. This limit is determined by the car's engine power, transmission, and other mechanical factors. Attempting to increase a car's towing capacity can put excessive strain on the vehicle and lead to potential safety hazards. If you need to tow a heavier load, it is best to use a vehicle with a higher towing capacity or consider renting a truck or other larger vehicle.

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