- #26

- 108

- 34

Sure.

The answer in your picture was correct for the problem you assumed.

You assumed the 5N force was applied at the end of a 0.2m (20cm) handle. You then correctly calculated the answer for that problem at 1 N-m. (5N times 0.2 m)

So Aplus on the math and applying the Torque equation.

However, that was probably not their intended question. So you would not get the books answer.

You stated the books answer. So we will make some guesses as to what they intended by that answer.

You want to open that door! yes? so grab the handle of the door and pull on it ! let's say you are pulling on the handle with a force of 5N.

Now the door will open by pivoting on its hinges. So the pivot length is from the hinges to your hand (see picture). So how long is that?

Where is your hand? Did you grab the edge of the door? the door is 50cm long so your d would be 50cm if you did.

Did you grab the edge of the handle? The handle is 20 cm long, so you are only 30 cm away from the hinges. (50cm- 20 cm)

Did you grab the middle of the handle? The answer you gave from the book assumes you did because they took 20cm and split it in half. 20cm/2= 10 cm. In this case, then you are 40 cm away from the hinges.

A better problem statement by the company would clear up this misinformation !

Once you have defined the problem you are going to solve, you already know how to do the math. It is the force times the distance.

You gave us two different forces, 5N and 2N, so staying with the 5 N times 0.4 m gives an torque of 2.0 N-m. If the force was only 2N, then the answer is 0.8 N-m.

PROBLEM SOLVING TECHNIQUE.

when faced with a badly written problem (usually on a test), you want to write down how you read the problem. Draw a simple graphic. write down your equations. Apply the equations. And then check that your units cancel properly. If allowed, ask the teacher to clarify the problem.

Given that you solved an acceptable interpretation of the written problem correctly, I would have given you full credit if you came in and reviewed the test with me.

See attached graphic

If possible would you guide me at the basic level.

For me the ## \tau = F \times d ## equation is comprehensible.

The answer in your picture was correct for the problem you assumed.

You assumed the 5N force was applied at the end of a 0.2m (20cm) handle. You then correctly calculated the answer for that problem at 1 N-m. (5N times 0.2 m)

So Aplus on the math and applying the Torque equation.

However, that was probably not their intended question. So you would not get the books answer.

You stated the books answer. So we will make some guesses as to what they intended by that answer.

You want to open that door! yes? so grab the handle of the door and pull on it ! let's say you are pulling on the handle with a force of 5N.

Now the door will open by pivoting on its hinges. So the pivot length is from the hinges to your hand (see picture). So how long is that?

Where is your hand? Did you grab the edge of the door? the door is 50cm long so your d would be 50cm if you did.

Did you grab the edge of the handle? The handle is 20 cm long, so you are only 30 cm away from the hinges. (50cm- 20 cm)

Did you grab the middle of the handle? The answer you gave from the book assumes you did because they took 20cm and split it in half. 20cm/2= 10 cm. In this case, then you are 40 cm away from the hinges.

A better problem statement by the company would clear up this misinformation !

Once you have defined the problem you are going to solve, you already know how to do the math. It is the force times the distance.

You gave us two different forces, 5N and 2N, so staying with the 5 N times 0.4 m gives an torque of 2.0 N-m. If the force was only 2N, then the answer is 0.8 N-m.

PROBLEM SOLVING TECHNIQUE.

when faced with a badly written problem (usually on a test), you want to write down how you read the problem. Draw a simple graphic. write down your equations. Apply the equations. And then check that your units cancel properly. If allowed, ask the teacher to clarify the problem.

Given that you solved an acceptable interpretation of the written problem correctly, I would have given you full credit if you came in and reviewed the test with me.

See attached graphic