Find the mass of this boat using torque

In summary, the boat has a mass of 11 kg based on the change in weight of the trailer before and after the boat was moved. The boat was initially supported by a scale reading 48 kg, but when it was moved 0.15 m further back on the trailer, the scale read 37 kg. This indicates that the boat weighs 11 kg.
  • #1
Format
87
0
A Trailer carrying a boat is supported by a scale which initially reads 48-kg. The boat (and therefore its centre of gravity) is moved 0.15-m further back on the trailer. The scale now reads 37-kg. Find the mass of the boat.

Kinda looks like this:

_______\___boat___/__
______|_______________O_______________
|------6.0-m-----|

Well, I've been tryin this question for 30 mins and i can't seem to get the right answer. I know F(d) = F(d) (where 'd' is the distance from the pivote)
but i don't know how to solve for the mass. If any of you can figure out my diagram and know wut to do...please help lol :smile:

Edit: k forget the diagram its just confusing lol. Just remeber that the boat is on a trailer with one point on the scale and then 6 meters away is the wheel. So there are 2 pivots.
 
Last edited:
Physics news on Phys.org
  • #2
The answer is 11 kg.First, calculate the weight of the trailer and boat before the displacement: 48 kg. Then, calculate the weight of the trailer after the displacement: 37 kg. The difference between these two is 11 kg, which is the weight of the boat.
 
  • #3


To find the mass of the boat using torque, we can use the equation: torque = force x distance. In this scenario, the force is the weight of the boat and the distance is the distance from the pivot (scale) to the center of gravity of the boat. We can set up two equations using this information:

Equation 1: initial torque = final torque
Initial torque = (48 kg)(6.0 m) = 288 kg*m
Final torque = (37 kg)(6.15 m) = 226.05 kg*m

Equation 2: torque = force x distance
(48 kg)(6.0 m) = force x (6.0 m - x)
Where x is the distance from the pivot to the center of gravity of the boat when it is moved 0.15 m back.

Solving for x, we get x = 5.85 m. This means that the center of gravity of the boat is 5.85 m away from the pivot (scale) when it is moved 0.15 m back.

Now, we can plug in this value for x into equation 2 to find the force (weight) of the boat:
(48 kg)(6.0 m) = force x (6.0 m - 5.85 m)
force = 48 kg

Therefore, the mass of the boat is 48 kg.
 

1. How do you use torque to find the mass of a boat?

To find the mass of a boat using torque, you will need to know the distance from the pivot point where the boat is balanced, the weight of the boat, and the force applied to balance the boat. The formula for finding mass using torque is: Mass = (Torque x Distance from pivot point) / (Acceleration due to gravity x Force applied).

2. What is torque and how does it relate to finding the mass of a boat?

Torque is a measure of the rotational force applied to an object. It is calculated by multiplying the force applied by the distance from the pivot point where the object is balanced. In the case of finding the mass of a boat, torque is used to balance the boat and determine its weight.

3. Can torque be used to find the mass of any object or just boats?

Torque can be used to find the mass of any object, not just boats. The same formula can be applied to any object as long as you have the necessary measurements of force, distance, and weight.

4. Are there any limitations to using torque to find the mass of a boat?

There are a few limitations to using torque to find the mass of a boat. First, the boat must be in a balanced position in order to accurately measure the torque. Second, the formula assumes that the boat is in a vacuum with no external forces affecting its balance. Finally, the measurements of force and distance must be precise in order to get an accurate result.

5. Are there any alternative methods for finding the mass of a boat?

Yes, there are other methods for finding the mass of a boat. One alternative is to use Archimedes' principle, which states that the buoyant force acting on an object is equal to the weight of the fluid it displaces. This method involves submerging the boat in water and measuring the weight of the displaced water. Another method is to use a scale to directly measure the weight of the boat. However, using torque is a more common and practical method for finding the mass of a boat.

Similar threads

  • Introductory Physics Homework Help
Replies
3
Views
2K
Replies
6
Views
784
  • Introductory Physics Homework Help
Replies
4
Views
4K
  • Introductory Physics Homework Help
Replies
30
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
3K
  • Introductory Physics Homework Help
Replies
4
Views
6K
  • Introductory Physics Homework Help
Replies
2
Views
868
  • Introductory Physics Homework Help
Replies
7
Views
3K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
1K
Back
Top