# What is Motion in 2d: Definition and 32 Discussions

Motion capture (sometimes referred as mo-cap or mocap, for short) is the process of recording the movement of objects or people. It is used in military, entertainment, sports, medical applications, and for validation of computer vision and robotics. In filmmaking and video game development, it refers to recording actions of human actors, and using that information to animate digital character models in 2D or 3D computer animation. When it includes face and fingers or captures subtle expressions, it is often referred to as performance capture. In many fields, motion capture is sometimes called motion tracking, but in filmmaking and games, motion tracking usually refers more to match moving.
In motion capture sessions, movements of one or more actors are sampled many times per second. Whereas early techniques used images from multiple cameras to calculate 3D positions, often the purpose of motion capture is to record only the movements of the actor, not their visual appearance. This animation data is mapped to a 3D model so that the model performs the same actions as the actor. This process may be contrasted with the older technique of rotoscoping.
Camera movements can also be motion captured so that a virtual camera in the scene will pan, tilt or dolly around the stage driven by a camera operator while the actor is performing. At the same time, the motion capture system can capture the camera and props as well as the actor's performance. This allows the computer-generated characters, images and sets to have the same perspective as the video images from the camera. A computer processes the data and displays the movements of the actor, providing the desired camera positions in terms of objects in the set. Retroactively obtaining camera movement data from the captured footage is known as match moving or camera tracking.

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1. ### Relative Velocity and Angles of Movement (Sears & Zemansky's Exercise)

The official solution says ±25.4°, but I'm having trouble reproducing it. Here is my solution: 1) The components of the velocity of firework F with respect to the ground G in the moment of explosion are the following (Notice, I'm using sin, because the statement says 30.0° from vertical.)...
2. ### Find focal length of electron for a parabolic motion

Here I was going to use ##\int \vec F \cdot d\vec l = \frac{1}{2}mu^2## What I got that is ##l=\frac{mu^2}{2eE}##. Here the question is what is ##l## (I took ##x## while doing the work but here I used ##l## instead of ##x##)? I was assuming that it's ##x## since I am calculating work in the...
3. ### Displacement of clock arm

I calculated the angle as 225 whereas answer says something else.

5. ### River Boat Problem: Minimizing Travel Time

From equation (3.7) , we know t = d/v_y = d / v_ABcosθ = d/ v_Asinβ Now for time to be minimum , denominator must be maximum this implies θ=0 and β=90, but this doesn't make sense as when we try to row the boat at 0 degree with y-axis due to stream it will have a some net velocity which will...
6. ### Projectile motion problem (moving ships firing a projectile)

Question : Solution attempt :
7. ### Throwing Objects - Motion in Two Dimensions

I stuck on part c and d. My attemption is attached.
8. ### Projectile Motion in 2D: Solving for Maximum Range in Inclined Planes

I know the conventional method for solving this question using the formula for maximum range of a projectile in an inclined plane, but since it is an objective problem, if we consider a non general case where α=0, then clearly we can see that (see attachment) only one option matches which...
9. ### Finding the y-component of a velocity vector

The first thing I did, was to find the equations for player A (p) and ball's (b) path (for each i and j component I used the equation I wrote in the relevant equations) and then I found the derivative of both equations so I could have the velocity: \vec{r}_p(t)=(6t^2+3t)\hat{i}+20\hat{j}...
10. ### Motion in 2 Dimensions & Relative velocity

Homework Statement The water in a river flows uniformly at a constant speed of 2.50 m/s between parallel banks 80.0 m apart. You are to deliver a package across the river, but you can swim only at 1.50 m/s. (c) If you choose to minimize the distance downstream that the river carries you, in...
11. ### Why Vertical Velocity changes & Horizontal does not?

Projectile motion involves velocity in vertical and horizontal direction. It is important to understand that the two are independent of each other. Solving problems becomes much easier with this simple understanding.
12. ### Finding the minimum distance between two cars

Homework Statement We have two cars moving like the picture. we want to find their minimum distance using relative motion. I) Consider a coordinate system on M, which has two axis. one axis is in direction of MP and the other is perpendicular to that (Something like r_hat and θ_hat). Find the...
13. ### Solving Force and Motion: Pulling 25.0 kg Sled 25m

<< Mentor Note -- New poster has been reminded to use the Homework Help Template when posting schoolwork questions >> A 25.0 kg sled is pulled (assume frictionless) with a force of 15.0 N at an angle of 20 degrees above the horizontal. (a.) How long will it take to pull the sled 25m? (b.) How...
14. A

### How to calculate projectile off cliff when angle is below th

Homework Statement Cliff is 50 m tall Stone thrown downwards with velocity of 12 m/s and 22 degrees below horizontal What is the time it will take to hit the ground? Homework Equations V=d/t D= Vi t + 1/2at^2The Attempt at a Solution Vx1= cos (22)(12) = +11.12620625 Vy1= sin (22) (12) =...
15. S

### Find angle between displacement and velocity vector

Homework Statement A stone is thrown at 25m/s and at 37 degrees above the horizontal from a 20m high building. Take g=10m/s2 Let D be the displacement vector from launch point on top of the building to landing point on the ground, and v be the velocity vector on impact, what is the angle...
16. ### Motion in 2D: Find Which Ball Hits Circle First?

Homework Statement Two balls A and B simultaneously start to roll down without friction along two different chords of a circle as shown in the figure. Find which ball will hit the circle first? (image attached) 2. The attempt at a solution I have divided the velocity of the balls into vector...
17. ### Ball, projectile motion in 2D

Homework Statement In a friendly game of handball, you hit the ball essentially at ground level and send it toward a wall 4.6 m away. The ball is hit with a speed of 20 m/s at 40 degrees above the horizontal. a.) At what height does the ball strike the wall? b.) Calculate the speed of...
18. ### Particle Motion in 2D

Homework Statement A block of ice starts from rest on an apartment building’s roof, which slopes at 41° below the horizontal. The block slides down the icy frictionless roof for 5.0 m and then leaves the edge, which is 12 m above the ground. a. How far from the building does the block strike...
19. ### Projectile Motion in 2d with Drag

Homework Statement So, I'm building a "Monkey Gun" and I want to be able to find the instantaneous velocity of my dart at a certain time. I shoot the gun at some angle, θ. The problem is, if I divide the velocity into x and y components, each depends on and impacts the other (the force from...
20. ### Ferris Wheel question (Motion in 2d)

1. The Ferris wheel [...] rotates counterclockwise, is just starting up. At a given instant, a passenger on the rim of the wheel and passing through the lowest point of his circular motion is moving at 3.00 m/s and is gaining speed at a rate of 0.500 m/s^2 . 2. Find the direction of the...
21. ### Solving a Rolling Bead's Motion in 2D Space

Homework Statement a If the bead starts at the origin at time t=0, how long does it take for it to reach the end of the track (30m away in the figure)? Provide the answer in terms of v_{}. b How does the parameter α depend on time, ie. what is α(t)? d What is the velocity vector as a...
22. ### Vectors and motion in 2D (physics problem)

vectors and motion in 2D (physics 1111 problem!) The bacterium Escherichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. When grown in a uniform medium rich in salts and amino acids, these bacteria swim along zig-zag paths at a constant speed...
23. ### Motion in 2D astronaut orbiting moon

Homework Statement The astronaut orbiting the Earth in Figure P4.32 is preparing to dock with a Westar VI satellite. The satellite is in a circular orbit 700 km above the Earth's surface, where the free-fall acceleration is 8.12 m/s2. Take the radius of the Earth as 6400 km. 2. Relevant...
24. ### Motion in 2D Question

Please Help! Motion in 2D Question Homework Statement A student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of 15.0 m/s. The cliff is h = 26.0 m above a flat horizontal beach, as shown in Figure P3.24. Homework Equations How long after...
25. ### Relative Motion in 2D - a plane & wind speed.

Homework Statement A plane attains an airspeed of 620 km/hr. The plane sets out for a destination 1085 km to the north (a 0° course) but discovers that the plane must be headed 20° east of north to fly there directly. The plane arrives in 2.00 h. What is the wind speed? What is the direction...
26. ### Projectile Motion: Time, Distance, and Velocity in 2D

A cannon ball is fired horizontally at a speed of 1000.0m/s from a height of 200.0m a.) How long does it take for the ball to land? 6.39s b.) Where does it land? 6390m c.) What is its velocity when it lands? I get the a and b part...but i just don't understand what am i...
27. ### Solving 2D Jumping Motion Homework

Homework Statement A man jumps from the top of a building to the top of another building 3.7 meters away. After a running start he leaps at an angle of 14 degrees with respect to the flat roof while traveling at a speed of 5.1 m/s. The acceleration of gravity is 9.81 m/s/s. To determine if he...
28. ### Finding the Angle of Release for a Dive-Bomber in 2D Motion

Homework Statement A dive-bomber has a velocity of 280 m/s at an angle of \vartheta below the horizontal. When the altitude of the aircraft is 2.15km it releases a bomb, which subsequently hits a target on the ground. The magnitude of the displacement from the point of release of the bomb to...
29. ### Motion in 2d w/ constant acceleration

Homework Statement In a tv set, an electron beam moves with horizontal velocity 2.7 x 10^7 m/s across the cathode ray tube and strikes the screen, 42 cm away. The acceleration of gravity is 9.8 m/s^2. How far does the electron beam fall while traversing this distance? Answer in units of m...
30. ### Motion in 2D snowball problem

Homework Statement A snowball picks up speed and rolls of a barn roof angled at 40 degrees from horizontal. The edge of the barn is 15.0 m above the ground, and the snowball has a speed of 7.00 m/s as it leaves the roof. Ignore air effects. How far from the edge of the barn does the...
31. ### How do I solve for time in seconds?

Motion in 2D! Help Homework Statement A stone is thrown upwards from the top of a building at an angle of 30 degree to the horizontal and with an initial speed of 20 m/s. The point of release is 45 m above the ground. (a) How long does it take the stone to hit the ground? 2. Homework...
32. ### Motion in 2D ball throw

A ball is thrown toward a cliff of height h with a speed of 30 m/s and an angle of 60degrees above horizontal. It lands on the edge of the cliff 4.0 s later.What was the maximum height of the ball? I try using this equation: y_f=y_i+v_iy(deltaT)+.5a_y(deltaT)^2 for y_i, i have 0 for v_iy i...