Does the scalar of Weight (W) = mg all the time?

In summary, the question is about finding the force of gravity on the x-axis for an object on a 40 degree angle using the weight of the object, which is given as 80N. The solution is to divide the weight by 9.8 and use the resulting value for mass in the equation mgsin(theta). The angle of incline does not affect the weight of the object.
  • #1
NYGooner
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I have a question in my textbook where I'm given weight of a "penguin in a sled" as 80N but the object is on a 40 degree angle. Is it telling me that on a normal flat surface the weight is 80N so that way to figure out the force of gravity on the x-axis I must divide the W by 9.8 then plug in my m (mass) that I get to find for the force of gravity along the x-axis as: mgsin(theta)? In the solution that a user posted on slader, they said to find mass its W/9.8 even though the object is being used on a incline of 40 degrees?
 
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  • #2
NYGooner said:
I have a question in my textbook where I'm given weight of a "penguin in a sled" as 80N but the object is on a 40 degree angle. Is it telling me that on a normal flat surface the weight is 80N so that way to figure out the force of gravity on the x-axis I must divide the W by 9.8 then plug in my m (mass) that I get to find for the force of gravity along the x-axis as: mgsin(theta)? In the solution that a user posted on slader, they said to find mass its W/9.8 even though the object is being used on a incline of 40 degrees?
Doesn't matter what the angle of incline is. The penguin could be climbing up the side of a cliff (angle to the horizontal = 90°), and W = mg for teh penguin.

Think about what is going on. The weight of the penguin (or any object) is produced by the object's attraction to the earth, not some random object nearby. As such, the force vector which we call an object's weight, will have a certain direction, which doesn't change:

free-body-force-diagram-block-on-frictionless-incline.png
Although the weight of an object doesn't change, the same can't be said for any contact forces between the object and an inclined surface, for instance, as you can see in the diagram above.
 
  • #3
Just to add: A weight is a force and thus never a scalar!
 

FAQ: Does the scalar of Weight (W) = mg all the time?

1. What is the scalar of weight (W)?

The scalar of weight (W) is a measure of the force of gravity acting on an object. It is commonly represented by the equation W = mg, where m is the mass of the object and g is the acceleration due to gravity.

2. Does the scalar of weight (W) always equal mg?

Yes, the scalar of weight (W) always equals mg, as long as the object is in a constant gravitational field and is not experiencing any other forces.

3. How is the scalar of weight (W) different from mass?

The scalar of weight (W) is a measure of the force of gravity acting on an object, while mass is a measure of the amount of matter an object contains. Weight can vary depending on the strength of the gravitational field, but mass remains constant.

4. Can the scalar of weight (W) be negative?

Yes, the scalar of weight (W) can be negative if the object is in a downward gravitational field, such as in freefall. In this case, the weight would be acting in the opposite direction of the gravitational force, causing it to have a negative value.

5. How does the scalar of weight (W) affect an object's motion?

The scalar of weight (W) is a force, so it can affect an object's motion by causing it to accelerate in the direction of the force. This means that objects with a larger weight will experience a greater force of gravity and accelerate faster than objects with a smaller weight.

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