# Vector problems

• Jul 30th 2012, 10:40 AM
Latsabb
Vector problems
I did a worksheet that I found online, and I swear three of the answers are wrong. I double checked my work, put it into a triangle solver online, and I keep getting the same results. I was hoping someone could just verify that my answers are correct.

Question 1:
Two forces with magnitudes of 40 pounds and 42 pounds are applied to an object. The magnitude of the resultant is 31 pounds. Find the measurement of the angle between the resultant vector and the vector of the 42 pound force to the nearest whole degree.

Angle: 25*

Angle: 47*

Question 2:
Vector u has a magnitude of 53 and a direction of 0*. Vector v has a magnitude of 10, and a direction of 295*. Find the magnitude and direction of the resultant to the nearest whole number.

Magnitude: 50
Angle: 11*

Magnitude: 58
Angle: 351*

Question 3:
Vector u has a magnitude of 27 and a direction of 40*. Vector v has a magnitude of 34 and a direction of 58*. Find the magnitude and direction of the resultant to the nearest whole number.

Magnitude: 60
Angle: 9* (this is rounded to a bad answer, due to rounding the magnitude, and then to the nearest whole degree)

Magnitude: 73
Angle: 44*
• Jul 30th 2012, 08:18 PM
Prove It
Re: Vector problems
Are you using * to represent "degrees"?
• Jul 31st 2012, 10:59 PM
earboth
Re: Vector problems
Quote:

Originally Posted by Latsabb
I did a worksheet that I found online, and I swear three of the answers are wrong. I double checked my work, put it into a triangle solver online, and I keep getting the same results. I was hoping someone could just verify that my answers are correct.

Question 1:
Two forces with magnitudes of 40 pounds and 42 pounds are applied to an object. The magnitude of the resultant is 31 pounds. Find the measurement of the angle between the resultant vector and the vector of the 42 pound force to the nearest whole degree.

Angle: 25*

Angle: 47*

Question 2:
Vector u has a magnitude of 53 and a direction of 0*. Vector v has a magnitude of 10, and a direction of 295*. Find the magnitude and direction of the resultant to the nearest whole number.

Magnitude: 50
Angle: 11*

Magnitude: 58
Angle: 351*

Question 3:
Vector u has a magnitude of 27 and a direction of 40*. Vector v has a magnitude of 34 and a direction of 58*. Find the magnitude and direction of the resultant to the nearest whole number.

Magnitude: 60
Angle: 9* (this is rounded to a bad answer, due to rounding the magnitude, and then to the nearest whole degree)

Magnitude: 73
Angle: 44*

1. I've attached sketches drawn to scale of the 3 questions.

2. You have to differ thoroughly between an included angle (qu #1) and a direction. The direction needs a reference value: With maps the direction North (not Norge!) is defined as 0°. With my sketches the positive x-axis is pointing in the direction 0°.

(For instance: In question #3 you tried to determine the angle between the resultant force and the first force, that means you answered a question which wasn't asked)

3. Check your arithmetic - and: It looks like as if some of the answers given in your workbook are not correct.