1. ### Two Charged Balls on Strings

Given the total angles in the x direction, I set up this: (mg/cos(x))*sin(x)-Fe=0 then isolated for x: mgtan(x)=(kq^2)/(2*sin^2x) sin^2(x)*tan(x)=(kq^2)/(2mg) From here I am stuck. How do I go forward when x is contained in two different trig functions on the left?
2. ### CoM reduced by total body height when bending your knee X degrees

Lets say that a man with a standing height of 185cm bent his knee 30 degrees, how many centimeters will be reduced from his standing height? Assume his femur length is 60cm and his tibia (shin) length is 50cm. Can anyone give me a hint? I've tried to use trigonometry but i dont think i fully...
3. ### A kid slips off the top of the hill -- find the escape angle

Hi, This is my try. Are you in agreement with this ? Thanks.
4. ### 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.
5. ### I Tensor calculation, giving|cos A|>1: how to interpret

On pages 42-43 of the book "Tensors: Mathematics of Differential Geometry and Relativity" by Zafar Ahsan (Delhi, 2018), the calculation for the angle between Ai=(1,0,0,0) (the superscript being tensor, not exponent, notation) and Bi=(√2,0,0,(√3)/c), where c is the speed of light, in the...

7. ### How does the release angle of a catapult affect the object's velocity?

[Moderator: repeated text removed.]
8. ### Slope Problem

Im really stuck with this problem ! any help would be much appreciated
9. ### I Flow (liquid or gas) across a rotating surface's face

<< Mentor Note -- Two threads on the same question merged into one thread >> How does the maximum Power equation change if there's an angle to the way the wind falls into the wind turbine's blades? Example, when it falls vertically to the blades, it's Pmax= 8/27Sρu13 But if there's for...
10. ### Double slit intensity question

Homework Statement Homework Equations (1) Φ = 2π*(dsinθ/λ) (2) Itotal = I0 cos2(Φ/2) (3) Itotal = I0 cos2(πdy/λR) λ = 585 * 10-9 m R = 0.700 m d = 0.320 * 10-3 m y = ? The Attempt at a Solution a) I used eqn (1) and divided the total oscillations by a complete oscillation to find the...
11. ### What is the minimum force at this angle that will move the box?

Homework Statement [/B] 2. Homework Equations Fs = Nμ W = mg Fy = Fsin(θ) Fx = Fcos(θ) The Attempt at a Solution [/B] Hello all at PhysicsForums, I have a question on angled force and static friction. From my attempt below, I think I have found the maximum force required and would need...
12. ### Converting PyGame 2 axis joystick float to 360 angle

I would like to convert my joystick's two axis float (horizontal and vertical) to a 360 angle that can be used to set a players direction in my game. From my research, I've found the best route to take is using Atan2. Variables: self.rot = 0 horaxis = joy1.get_axis(0) veraxis = joy1.get_axis(1)...
13. ### Finding the angle in which the resultant force points

Homework Statement Forces of 11.8N north, 19.2N east, and 15.9N south are simultaneously applied to a 3.93kg mass as it rests on an air table. What is the magnitude of its acceleration? What is the direction of the acceleration in degrees? (Take east to be 0 degrees and counterclockwise to be...
14. ### 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...
15. ### Map question involving vectors (find the angle)

Homework Statement Instructions for finding a buried treasure include the following: Go 66.0 paces at 256deg, turn to 140deg and walk 125 paces, then travel 100 paces at 169deg. The angles are measured counterclockwise from an axis pointing to the east, the +x direction. Determine the resultant...
16. ### Vector Addition Question: find angle (A+B & A-B)

Homework Statement Two vectors A and B have precisely equal magnitudes. For the magnitude of A + B to be 65 times greater than the magnitude of A - B, what must be the angle between them? Homework Equations The Attempt at a Solution I tried using the dot product and solving for the angle but...
17. ### River question (looking for angles and headings)

Homework Statement A child in danger of drowning in a river is being carried downstream by a current that has a speed of 2.35km/h. The child is 0.505km from shore and 0.780km upstream of a boat landing when a rescue boat sets out. If the boat proceeds at its maximum speed of 18.8km/h relative...
18. ### Resultant Vector

According to my understanding, option D is the only possible value of R. I don't understand how options A, B and C are included. Please explain this question. Thanks. (regards)
19. ### A Binary fractal tree with equidistant leaves on a circle

Does there exist a binary fractal tree… (reference: http://ecademy.agnesscott.edu/~lriddle/ifs/pythagorean/symbinarytree.htm ) …whose leaves (endpoints) lie on a circle and are equidistant? Consider a binary fractal tree with branches decreasing in length by a scaling factor r (0 < r < 1) for...
20. ### Constraint of Two blocks on an inclined plane

Hello, I have an issue regarding a constraint related to an angle: Suppose I have masses 'A' and 'B' on an inclined plane ( of mass 'C') attached by a pulley. I place my origin as shown and I want to find a constraint relating angle β. so, I saw my classmate writing as follows to find...
21. ### Is it all in the angle?

For one of my current projects in computer vision (which really is a study in point clustering and tracking in a data stream of n-dimensional data), I have come up with a way to very quickly index a 2D angle between two points or the angle of a vector. Doing a little bit of investigation, and...
22. ### Pulling an object at an angle with friction -- find the Kinetic Energy

Homework Statement A boy pulls a sled (mass m=59.2 kg) along the ground using a force of magnitude F = 586 N inclined at an angle of θ=37.3° to the horizontal. There is friction between the sled and the ground with a coefficient of µk = 0.205. If the sled starts at rest, how much kinetic energy...
23. S

### Coulomb's Law, Three Charges, X Y Components, Angle

Homework Statement This is finding net force on Q3. I was taught by my Physics teacher to always get angle from the Positive side of x-axis (+X-Axis). For example in the above situation, if the angle is -30deg from the +x-axis (assuming the Q3 is the origin), Why is F31 x-component = 140...
24. ### Projection at an angle - throwing stones

Hello everyone. I have this problem: 1. The problem statement, all variables and given/known d I throw stone from height h at an angle α, then at an angle β (so I know h, α, β). I throw it with same velocity v. The stones fall in same distance d. The question is: find the d (distance) and v...
25. ### I Calculation of the hour angle of the Sun

Hi all, According to the sunrise equation, the hour angle of the sun at sunset is: cos H = -tan(a)tan(d) where H = the hour angle, a = latitude and d = solar declination angle. This equation says that H at sunset = -H at sunrise. Now, I have a few questions concerning that: 1) I was...
26. ### Refraction in Cylinder.

Homework Statement A non-transclucent container in the form of a cylinder, has a diameter of 3.00 m, has its top part open, and is filled with water. When the sun created a 28.0 degree angle with the horizontal, the light doesn't illuminate the bottom of the container. What's the depth of the...
27. ### B If air drag is a factor, how will it affect a projectile?

If air drag is a factor, how will it affect a projectile’s trajectory qualitatively? Its velocity? Its acceleration?
28. ### I Angle between vectors via scalar product vs vector product

Hello, I have a question about why I can't determine the angle between two vectors using their cross product. Say there are two vectors in the XY-plane that we want to find the angle between: A = -2.00i + 6.00j B = 2.00i - 3.00j The method to do this would be to work out the scalar product of...
29. ### Find new location -- 2-wheeled car/robot

Hello, everyone! Now I'm trying to develop 2 wheels robot, which travels along the line simulator. The robot can turn only by increasing velocities of each wheel. The conditions are below: - I know velocities of 2 wheels - I know radius between wheels The task is next: How to find new location...
30. ### B Average angle made by a curve with the ##x-axis##

The average angle made by a curve ##f(x)## between ##x=a## and ##x=b## is: $$\alpha=\frac{\int_a^b\tan^{-1}{(f'(x))}}{b-a}$$ I don't think there should be any questions on that. Since ##f'(x)## is the value of ##\tan{\theta}## at every point, so ##tan^{-1}{(f'(x))}##, should be the angle made by...