# force

1. ### Angular Momentum

So to prove angular momentum (L = r x p) is conserved, I have to prove the derivative of L = 0. The proof I have is the derivative of L = (ṙ × p) + (r × ṗ) = 0 + r × F = 0 (Sorry about the formatting, really new here). I don't understand 1) Why (ṙ × p) = 0 2) Why r × F = 0...
2. ### Fluid Force

A rectangular box with height 2m, width 3m, and length 4 m is submerged in a pool of water. The top of the box is 5m below the surface of the water. Compute the fluid force on one of the box sides with dimensions 4m by 2m. A rectangular tank with a square base of side length 4 feet by 3 feet in...
3. ### conservative force fields

why the vector F is conservative if and only if exists a scalar function? If there's no scalar function, the F is said to be not conservative?
4. ### Why do you force factor out on X to find the Horizontal Asymptote?

I understand that if the exponents of the leading coefficients are the same, then the HA is just those leading coefficients divided. But i've been told that the true way to find it is by force factoring out an x, and plugging in x as it approaches infinite. Can someone explain why?
5. ### Calculating Force in Beams

Trying to work out the forces in each beam for this question (3.(b)(i)) as attached below. I've got the lengths using Pythagoras: AB = 1.5m BC = 2m AC = 2.5m Angle at A = 45 degress B = 90 degrees C 45 degrees Answers are as follows: FBC = 120kN FAB = 90kN FAC = 96kN This is my attempt...
6. ### Force Diagrams

Hi , Im working through this activity for my engineering degree Im a little bit lost on this question. I had a go at drawing the force diagram myself and came up with the top drawing. When I checked againt the universities, they had done it a completley different way. First of all I thought...
7. ### force and potential energy

Hello, I'm new to this forum and was wondering if somebody/anybody could help me with these questions, I'm not sure if this is posted in a correct area in this forum so apologies if it isn't. If a particle of mass 1kg is acted on by a net conservative force given by F = -2x+x^2+2x^3, where F...
8. ### Is there a formula to determine force based off mass, distance and angle?

I am currently studying forces in Physics, and the professor basically just gave the definition of tension force, and the book isn't helping me with a problem that appears to be using tension force. Basically, the problem involves a rope strung across a 10 meter gap between two buildings. The...
9. ### Linear Speed - Torque

Suppose the force Ft in the cord hanging from the wheel is given by the relation Ft = 3t - 0.2t^2 (newtons) where t is in seconds. If the wheel starts from rest, what is the linear speed of a point on its rim 8 s later? The Ft force is perpendicular to the wheel's (4 kg) radius = 33 cm. The...
10. ### Hydrostatic Force

An aquarium 6 ft long, 3 ft wide, and 4 foot deep is full of water. What is the hydrostatic force coming from the bottom, and from one side? a. (from bottom) P = (62.5)(d) = (62.5)(4 ft) = 250 F = (P)(w)(l) = (250)(3 ft)(6 ft) = 4500 lb/ft^{3} ?? b (from side) F = \int_{0}^{d}...
11. ### Hydrostatic Force on a submerged plane.

Hello, I am having trouble with question 5, it reads (ignore the Riemann sum part) : Here is what I did, and where did I go wrong?. The answer the book gives is: $6.7\cdot 10^4N$. Thank you, -Sakon
12. ### Hydrostatic force

Hello, Calculating Hydrostatic force is driving me crazy (Question 9). I have tried to set up an x-coordinate as follows but I am not getting the correct answer. Where did I go wrong. Could someone please explain to me, and what are your tips/tricks? Thank you, -Sakon
13. ### Calculating Angle of an Inclined Plane for a known Force Vector Value

I have a pallet of goods for transport, weighing 100kg. I require the goods to be restrained from forward movement by .8g or 80% of the pallet weight to counter vehicle braking forces. Using the Trigonometric method of Vector Resolution, I have established that the Fw II (Red) Vector has a...
14. ### Calculating Force due to pressure.

Hello, I am stuck on this ( what I think) calculus involved physics problem. My first concern is my approach at integration the correct method? Is there an easier way? Well, I know that the force to be applied is : F = xk = 9.375 N and this force is due to the continually increasing...
15. ### Buoyant Force

Hello, The buoyant force = density of displaced liquid * volume of the same liquid ( or the object submersed?) * gravity. My question is: Is the volume of liquid displaced = the volume of the object submersed in water? I think this is true because it would not make sense otherwise. Thank...
16. ### Fluid Force Problem - # 3

(Triangular Plate) Calculate the fluid force on one side of a plate, which is submerged 2 ft below the pool surface, and has (the triangular plate) a height of 3 ft. F = \int_{a}^{b} (w)(strip depth) (L(y)) dy F = \int_{0}^{3}(62.4)(5 - y) 2y dy ??? Note the vertices of the traiangle are...
17. ### Fluid Force Problem - # 2

In a pool filled with water to a depth of 10ft, calculate the fluid force on one side of a 3ft by 4ft rectangular plate if the plate rests vertically at the bottom of the pool. (a). on it's 4-ft edge (b). on it's 3-ft edge F = \int_{a}^{b} (w)(strip depth) (L(y)) dy (a). F =...
18. ### Fluid Force Problem

Calculate the fluid force on one side of a semi-circular plate of radius 5., that rests vertically on it's diameter at the bottom of a pool filled with water to a depth of 6ft. F = \int_{a}^{b} (w)(strip depth) (L(y)) dy F = \int_{0}^{5}(62.4)(6 - y) ?? dy What goes in the question mark? On...
19. ### Line of force

I cannot resolve part ii). The problem is the 176. Instead, I get 80. I don't necessarily need to be shown how to do it, but it would be good if someone can verify that the 176 is correct.
20. ### force vector and displacement

A force of 6N points to the upper right making an angle of pi/4 with the y-axis. the force acts on an object that moves along the ling segment from (1,2) to (5,4) a) find a formula for the force vector F = <6 cos pi/2, 6 sin pi/4> = < 3sqrt{2} , 3sqrt{2}> ?? b) find the angle between the...