1. ### Finding the angle between vectors a and m, knowing the magnitude of m and n

Summary: Finding angle between vectors a and m, knowing magnitude of m and n, also the angle between m and n with 60 degrees. Using geometry, it looks like the angle is 30 degrees but the answer is suppose to be 54.7 degrees. I'm not sure how to solve this.
2. ### I Main Sequence Rules

When viewing an HR diagram, the main sequence curve is apparent, and the general shape of it is obvious. However, in this truncated version, it's unclear to me exactly which stars should be considered main sequence. I've added a shaded grey area as what I think I should count as main sequence...
3. ### B Magnitude and Size

What's the difference between magnitude and size? I mean, how can I say that AB vector has a magnitude of 9 Newton, and its length is 4 cm.
4. ### Finding Vector Angle using cosine law

Homework Statement Vectors A and B have equal magnitudes of 4.93. If the sum of A and B is the vector 6.79j, determine the angle between A and B Homework Equations c^2 = a^2 + b^2 -2abcos(theta) The Attempt at a Solution I just rearranged the formula above so that I could solve for the...
5. ### Magnitudes and Comparison

Homework Statement You have decided to use a CCD camera to check if a 16th magnitude quasar is variable. With your telescope/camera combination, you know that a star with a magnitude of 0 would deliver 1 × 109 photons/second to one pixel, so this allows you to work out the photons/second from...
6. ### Vectors (Multiplication)

Homework Statement Homework Equations Is my solution correct? If not then please point out the mistakes and help me solve this question in the right way. Thanks in advance. The Attempt at a Solution
7. ### A frictionless incline with a block sliding down it...

A frictionless incline (the triangle below) is bolted to the floor so that it can not move. A block of mass m slides down the slope, which makes an angle with the horizontal. a)Draw a free-body diagram for the block, labeling all forces uniquely. b)Describe all the forces listed above in the...
8. ### Physics Vector Problem

Homework Statement You enter an antique classic car road rally with your 1956 Studebaker Golden Hawk. The rally course consists of the following segments: travel north at 25.0 m/s for 30.0 min, then east at 32.0 m/sfor 40.0 min, and finally northeast at 30.0 m/s for 50.0 min. For the entire...
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### Electrostatics? Magnitude and direction of a magnetic field

Homework Statement A force of 2.4N is exerted on a -1.8µC charge in a downward direction. What is the magnitude and direction of the magnetic field at this point? (The assignment sheet is called "Electrostatics Questions", hence the "Electrostatics?" in the title) Homework Equations Electric...
10. ### Finding the magnitude of velocity vector

Homework Statement A cricketer throws a 147g ball by exerting a force of 7.5N for 0.84s. If the launch angle is 39 degrees from horizontal, calculate the range of the ball. Homework Equations The Attempt at a Solution I have the range equation and I just need to find the magnitude of the...
11. ### Find Absolute Magnitude, distance and "T" of binary star system

This is the problem given at my basic astronomy course. If I turn it in within a month correctly, I get 10 extra points in the finals. Problem: We have binary star system consisting of Star A and Star B. Astronomers have observed it for 11 years, during which it has moved from point A to point...
12. ### Finding magnitude and direction of reaction force

Homework Statement A uniform horizontal rod of mass 4 kg and length 500 mm, is hinged at the left hand side and supported at rest by a chain (S) attached 10 cm from the hinge. Calculate the magnitude and direction of the reaction force on the rod at the hinge. State the principle you have...
13. ### Magnitude of charge with common Transparent tape

Homework Statement a) Common transparent tape becomes charged when pulled from a dispenser. If one piece is placed above another, the repulsive force can be great enough to support the top piece’s weight. Assuming equal point charges (only an approximation), calculate the magnitude of the...
14. ### Magnitudes and Directions In Uniform Circular Motion

Homework Statement A biker is 40.0m to the east of a flag in a park, heading south at 10m/s. 30.0 seconds later, the biker is 40.0m north of the flag and heading east at 10.0m/s. For the biker in this 30.0s interval, what are: a) the magnitude and direction of the displacement? b) the magnitude...
15. ### Statics: Dimensionless Unit Vector

Homework Statement Homework Equations The Attempt at a Solution So I began by subtracting. (205-160)=55 i (495+128)=623 j Both of these vectors are in the positive direction. So if I divide the vector by its magnitude I should get an answer of 1 in the positive direction for both i and...
16. ### "Vomit Comet" SpaceCraft (0)-V & H at Max Height

Homework Statement Physics for Scientists and Engineers, 8th Edition, Ex. 47 M4 A spacecraft flies from 24.000 ft to 31.000 ft, in which it enters a parabolic trajectory with a velocity of 143 m/s at an angle of 45, above the horizontal. It exits with a velocity of 143 m/s at an angle of 45...
17. ### Finding the magnitude of force P

Homework Statement Homework Equations F = ma The Attempt at a Solution My value for P does not make any sense. Why is this so?
18. ### How to solve for the magnitude and angle in this situation?

Homework Statement Each one of the force vectors are surrounded with dimensions. But you're not given any angles. How do you solve for the resultant vector like that? Homework Equations Fr = F1 + F2 + F3 The Attempt at a Solution I tried taking the arctan(200/210) on the 435 N...
19. ### Vector problem missing magnitude of two vectors

Homework Statement Force A has a magnitude of 200 lb and points 35deg N of W. Force B points 40deg E of N. Force C points 30deg W of S. The resultant of the three forces has a magnitude of 260 lb and points 85deg S of W. Find the magnitude of forces B and C. Homework Equations...
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### Finding the magnitude of a vector

Homework Statement [/B] If possible, refer to attached image rather than whats written below (as the image is easier to understand). Triangle ABC is equilateral and AD = BE = CF. Let u, v and w be unit vectors in the directions of AB, BC and CA respectively. Let AB = mu and AD = nu. i) Find BC...
21. ### Question on finding maximum magnitude of acceleration

Homework Statement An object is moving in the xy-plane according to the equations x(t) = 3sin(3t) and y(t) = 4cos(3t). What is the maximum magnitude of the particle's acceleration? 1) 5 m/s2 2) 15 m/s2 3) 30 m/s2 4) 36 m/s2 [the accepted answer] 5) 45 m/s2 Homework Equations...
22. ### Slider Crank Mechanism Magnitude and Direction

https://scontent-lhr3-1.xx.fbcdn.net/v/t34.0-12/13181084_10156883800920486_1357045350_n.jpg?oh=a39d7777f01c4aa06301c4f3d740de1e&oe=57301DBC Hi I am currently studying design engineering and my lecturer has left just before an exam. I really don't know how to find the magnitude and direction of...
23. ### Magnitude of velocity and acceleration

A car travels around a circular track with a radius of r=250m. When it is at point A then VA=5m/s which increases at a rate of a=(0.06t)m/s2. Determine the magnitude of its velocity and its acceleration when it is 1/3 around the track. My distance in this situation is obviously 524m. Can anyone...
24. ### Counting stars

Homework Statement (This is a long problem but I think the question is not hard.) Determining the star density from star counts is tough, but estimating counts from a density law is simpler. In practice, this method of fit-ting observed number counts to an assumed density law is becoming a...
25. ### How do I calculate the magnitude of initial acceleration?

Homework Statement A system consists of a bicycle and a cyclist travelling at a constant velocity along a horizontal road. The total resistive force acting on the system in 4.0N and its speed is 8.0 m/s. Calculate the useful power output of the cyclist. The cyclist stops pedalling and the...
26. ### K Corrections

So I'm trying to k-correct some fluxes in 250μm (janskys) using the M82 template found here and the relevant equations found here (I also have the transmission filter function). The template is normalised to 5500 A and doesn't have a brightness so I fail to see how I can correct my observed...
27. ### Magnitud VS. Component of a vector

Hello all. Sometimes, when reading a physics book, I find it difficult to distinguish between the magnitud of a vector and the component of a vector. For example, take the weight force, with the positive z direction pointing upwards (that is, F= -mg k). Sometimes, people write F=mg refering to...
28. ### Evaluate Magnitude of Gravitation at the Surface of a Planet

1. The trajectory of a rock thrown from a height with an initial speed of 20.9 m/s is shown in the figure below. Evaluate the magnitude of the gravitational field at the surface of the planet. The planet has no atmosphere...
29. ### Magnitude of Charges

Homework Statement I need to find the magbitude of charges Lenght of string - 50 cm mass of balls - 0.2 grams theeta - 37 degrees Homework Equations K-8.99x10^9 [/B] The Attempt at a Solution I found that half the distance between the balls is 15.9 cm but i dont know how to continue[/B]
30. ### Three vectors lie in an xy plane

Homework Statement Three vectors A, B, C, each have a magnitude of 46 m and lie in an xy plane. Their directions relative to the positive direction of the x axis are 28 ˚, 191 ˚, and 313 ˚. What are the magnitude and the angle of A-B+C with right-arrow in the range of (-180°, 180°)? Homework...