# What is 2d kinematics: Definition and 92 Discussions

TupiTube ( also known as Tupi 2D) is a free and open-source 2D animation software that is focused on usability for children, teenagers and amateur artists. It is available for Windows, Mac OS X, Unix-like operating systems and Android. This project is developed and maintained by the Colombian startup MaeFloresta. This project is covered under the terms of GPL-2.0-or-later.

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1. ### Confusion on relative velocity sign

The downstream part is no problem: c_E = c + v. My only question is why is the upstream velocity of Chris relative to the Earth c-v, as said by the textbook, and not v-c? Assuming v is to the right and positive, doesn't c become negative since it is in the opposite direction?
2. ### 2D kinematics problem -- Skateboard ramp jump calculations

So I tried the following: Getting the velocities for x and y V_xi = 5.2cos(30) = 4.5 V_yi = 5.2sin(30) = 2.6 Then I use v^2 = u^2 +2as to get the final velocities before she leaves the ramp: for V_x the final is the same as the initial since the equation becomes V_xf = V_xi for V_y the final is...
3. ### Find angles such that the motion travels a specific distance

We know the time it takes the water complete the whole parabola is (sin(x) * 6.5 * 2) / 9.8. So I come up with (sin(x) * 6.5 * 2) / 9.8 * cos(x) * 6.5 = 2.5, because the x component of the velocity is the same for the whole time. But I get the results like these: x≈0.30929171+πn,1.26150461+πn...
4. ### When to consider body fixed reference frame

Hello I am studying mechanics and I have been reading about having the reference frame fixed at a certain point, body fixed and also the gyro equations. I an identify the gyro case easily as I am looking for an AAC body which rotates about an axis. I am confused about the other two cases in...

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6. ### 2D kinematics -- Calculate the acceleration of the jumping athlete

this is my work but the answers say 11 m/s^2 so I made an error somewhere. Also if someone could help me with solving the direction for the acceleration, that would be greatly appreciated.
7. ### Pushing a stalled car out of an intersection

Hints given: -Start with free body diagram. Use the relationship between impulse and momentum to find the final velocity of the car after he has pushed for time t. -Use a kinematic equation to relate the final velocity and time to the distance traveled. -What is his initial velocity? My...
8. ### Am I setting up this kinematic equation properly?

A race car starts from rest and goes a quarter mile (1/4 mi) in 12.1 seconds. Assume the acceleration of the car is constant. (a.) What is the acceleration of the car? (b.) What is the final speed of the car? (c.) If you hit the brakes, how far would it take to stop the car if the breaks cause...
9. ### 2D Kinematics - Dropping object from a zipline

Homework Statement A 50m zipline is hung 11m off of the ground at its starting point (assume it ends at ground level). If you are to drop an object which is 20m along the ground from the start of the zipline, how far down the line would you need to let it go? Homework Equations d=((VF+VI)/2)*t...
10. ### Projectile trajectory problem with constraint

Homework Statement http://imgur.com/RDMG4Pj Link to drawn out problem^ The ball goes through the hoop NOT at the peak, but rather on it's downward path. It's asking for the total x-displacement, launch angle (theta), and the total flight time. It must me solved WITHOUT using the range...
11. ### Relationship between velocity, acceleration, and a circle?

The perimeter of a circle is 2πR (R=radius). [ref] Acceleration = Δv/Δt (v=velocity, t=time). [ref] Motion mathematics can always be reduced to multiple independent one-dimensional motions. [ref] The distance an object travels while accelerating = vit + at2/2 (a=acceleration, vi=initial...
12. ### Discrepancy with Toricellis equation in a 2D kinematics prob

Homework Statement A stone is thrown from a height 2.1m with an angle of 45 degrees. It fell to the ground 42 m from the throwing position, measured horizontally. Initial velocity is 19,81 m/s, flight time is 3s what is the maximum height? Homework Equations All 2D kinematics equations. The...
13. ### Using series in a 2D kinematics problem

Homework Statement A ball is rolling towards a rectangular hole which is 40cm deep and 2cm wide with a velocity 1m/s. It falls through the hole, bounces off the walls a couple of times and falls down. The direction of balls motion is perpendicular to the hole (falling in it from one side)...
14. ### Equations of Kinematics in 2-D/Projectile Motion

Homework Statement A tennis ball is struck such that it leaves the racket horizontally with a speed of 28.0 m/s. The ball hits the court at a horizontal distance of 19.6 m from the racket. What is the height of the tennis ball when it leaves the racket? Homework Equations v = vo + at x =...
15. ### Forces acting on two stacked blocks

Homework Statement A 1.5 kg block rests on top of a 7.5 kg block which are attached using a cord to a pulley - there is no friction anywhere. What force must be applied to the bottom block so the top block accelerates to the right at 2.5 m/s^2? Homework Equations m1 = 1.5kg a(to the right) =...
16. ### How Far Does a Ball Travel After Rolling Off an Incline?

Homework Statement A 30 degree inline sits on a 1.1 meter high table. A ball rolls of the incline with a velocity of 2m/s. How far does the ball travel acoss the room before reaching the floor?Homework Equations deltax= vot + 1/2at^2[/B] The Attempt at a Solution...
17. ### Finding the angle of projection and its speed in 2D Kinetics

Homework Statement : The trajectory of a projectile in a vertical plane is y = √3 x - (1/5)x2, where x and y are respectively horizontal and vertical distances of the projectile from the point of projection. Find the angle of projection and speed of projection.[/B]Homework Equations ...
18. ### Cannon shooting emergency packets

Homework Statement A cannon at ground level is shooting emergency packets to people stranded on the roof of a flooded building of height H=120 meters. The corner of the building is located a distance D=40 meters from the cannon. It is desired that the incoming packets are flying tangent to the...
19. ### Projectile Motion - Skier & Ramp

Homework Statement A ski jumper acquires a speed of 119.0 km/hr by racing down a steep hill. He then lifts off into the air from a horizontal ramp. Beyond this ramp, the ground slopes downward at an angle of θ = 45 degrees. Homework Equations Assuming the skier is in free-fall motion after he...
20. ### Projectile Motion- Incline vs. Horizontal Surface

Homework Statement Two identical metal blocks, H and A, are placed at equal heights on frictionless ramps as shown above. The blocks are released at the same time, travel down the ramp, and then slide off their respective ends of the table. Block H leaves the table from a horizontal surface...
21. ### 2D kinematics question (2nd year of undergrad level.)

Homework Statement An automotive test track forms a curve in the horizontal xy plane specified by y(x) =γx^3 / 2 where γ = 0.2 m^-1/2 and x ≥ 0 . A car moves along the track, starting at rest at the origin at time t = 0 , and picking up speed in accordance with v = ct , where c = 4.8 m s^-2 ...
22. ### Maximize Stone's Height Thrown From 56m Building - 2d Kinematics Help

Homework Statement A stone is thrown at an angle of 36.9 above the horizontal at 24.0 m/s from a building 56m high. What is the maximum height (with respect to the ground) that the stone reaches? Homework Equations - The Attempt at a Solution No clue. Have a picture drawn and all my knowns...
23. ### Finding the Optimal Archer Angle for Hitting a Moving Target on Planet Zorg

Hello everybody. Although this is just a kinematics problem, I am having a hard time figuring out what to do. The question is: An archer on the planet zorg spots an octomorph that is resting in a tree above water. The octomorph's position in the tree is 100m away horizontally and 100m...
24. ### How Do You Calculate the Minimum Speed of a Baseball for a Home Run in Physics?

I'm struggling to do this problem. "When Babe Ruth hit a homer over the 7.0m -high right-field fence 120m from home plate, roughly what was the minimum speed of the ball when it left the bat? Assume the ball was hit 1.0m above the ground and its path initially made a 30∘ angle with the ground."...
25. ### Calculating Missile Launch Time for 2D Kinematics Problem

An antitank gun which fires missiles with a speed of 240m/s is located on a 60m high plateau overlooking the surrounding plain. The gun crew sights an enemy tank 2200m from the base of the plateau. Simultaneously, the tank crew sees the gun and starts to head directly away from the plateau. The...
26. ### How Does Force Angle Affect Book Acceleration with Friction?

Homework Statement A book of mass M = .55 kg rests on a table where the coefficient of static friction us = .45. A force, F = 4 N acts on the book at an angle of 15 degrees above the surface of the table. What is the acceleration of the book if the coefficient of kinetic friction uk = .23...
27. ### 2D Kinematics Problem involving subtended angle

Homework Statement Mortar crew is near the top of a steep hill. They have a mortar. They angle this mortar at an angle of \theta = 65° . The crew fires a shell at a muzzle velocity of 228 ft/sec (69.5 m/s). How far down the hill does the shell strike if the hill subtends an angle of \phi =...
28. ### 2D Kinematics - 2 rocks off a bridge

2D Kinematics -- 2 rocks off a bridge Homework Statement Heather and Jerry are standing on a bridge 60m above a river. Heather throws a rock straight down with a speed of 14m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air...
29. ### What is the significance of h in relation to finding the distance AB?

Homework Statement http://postimg.org/image/bh4tzmd4l/ Can someone explain to me what "acceleration of the truck relative to the crate means"? What should I do first in trying to solve this?
30. ### What is the speed of the stone just before it hits the ocean?

Im sorry I just realized this is in the wrong subforum... Homework Statement Hello Everyone! I am new here and am having trouble with this webassign question. I was able to work out the answer to the first two but the last two are giving me trouble. I am not sure if this is right subforum to...
31. ### 2D Kinematics Problem dealing with acceleration

Homework Statement " An airplane turns slowly for 9.2s horizontally. The final velocity of the plane is 360km/hr [N]; the average acceleration during the turn is 5.0m/s^2 [W]. What is the initial velocity of the plane?" Homework Equations a=ΔV/t The Attempt at a Solution at=Δv...
32. ### 2D kinematics - Solved, but a question on the logic

The problem: (Note: the correct answer is bolded throughout) A basketball is launched with an initial speed of 8 m/s at a 45 degree angle from the horizontal. The ball enters the basket in 0.96 seconds. What is the distance x and y? Just ignore the distance x, I know it's simply the product...
33. ### Difficult 2D Kinematics Question

Homework Statement A basketball is thrown from a height of 2m. The direction of its velocity when it hits the rim of the basketball hoop is 45 degrees below the horizontal. The basketball hoop is 3m above the ground and 4.5 m in front of the shooter. How long does the ball take to hit the rim...
34. ### 2d Kinematics Problem Final Velocity

Homework Statement http://imgur.com/fGYf0 Stuck on #3 Homework Equations V = Vi + a*t Y = (1/2)gt^2 + (ViY * t) + Yi The Attempt at a Solution I have found the vertical and horizontal components and the initial velocity. ViX = 6.2 ViY = 9.922 Vi = 11.7 Yf = 0 Yi = 7 Xi =...
35. ### 2D kinematics - conveyer belt question

Homework Statement Sand moves without slipping at 6.0m/s down a conveyer belt that is tilted 15°. The sand enters a pipe 3.0m below the end of the conveyer belt. What is the horizontal distance between the conveyer belt and the pipe? Not sure where to start.
36. ### How Can I Solve 2D Kinematics Problems Using the Quadratic Formula?

Homework Statement A projectile is shot from the edge of a vertical cliff 60.0meters above the ocean. It has a speed of 100m/s and is fired at an angle of 35 degrees above horizontal. How far from the foot of the vertical cliff does the projectile land. Homework Equations Yf= Yinitial + ViT...
37. ### Cargo Planes and 2D Kinematics

A cargo plane is flying horizontally at an altitude of 10.9 km with a speed of 850 km/h when a large crate falls out of the rear loading ramp. (Ignore any effects due to air resistance.) (a) How long does it take the crate to hit the ground? (b)How far horizontally is the crate from the point...
38. ### How Much Does Gravity Affect a Baseball's Trajectory Over 18.4 Meters?

1. While trying out for the position of pitcher on your high school baseball team, you throw a fastball at 76.4 mi/h toward home plate, which is 18.4 m away. How far does the ball drop due to effects of gravity by the time it reaches home plate? (Ignore any effects due to air resistance and...
39. ### Physics 2d kinematics, projectile motion

Homework Statement Dr. Evil runs out to his car which is parked at the bottom of a hill that is inclined with the horizontal at 20(degrees) and blasts up the hill at an acceleration of 6 m/s2. James Bond runs out behind Dr. Evil to a mortar that is located conveniently exactly where Dr...
40. ### Check my Throw the Ball lab. (2D kinematics, force, work)

Check my "Throw the Ball" lab. (2D kinematics, force, work) Here I have a lab, with explanation, questions and my worked out answers (tried to make it as neat as possible with all the formulas I use, lowercase letters are subscript letters). Can someone carefully check my math for all this? I...
41. ### 2D Kinematics - Projectile Motion Question

Homework Statement A daredevil is shot out of a cannon at 33.7◦ to the horizontal with an initial speed of 25.5 m/s. A net is positioned at a horizontal distance of 43.7 m from the cannon from which the daredevil is shot. The acceleration of gravity is 9.81 m/s^2 At what height above the...
42. ### 2D Kinematics - Projectile Motion

Homework Statement A koala throws a eucalyptus branch. It goes 1.5 meters. If it left at 43 degrees, what velocity did the branch have when it left the koala's paw? The answer must be in vector form (m/s @ degrees). Needed: initial velocity Known: x-displacement = 1.5m x-acceleration =...
43. ### 2D Kinematics Problem w/ Coefficient of Friction?

I'm really lost on how to do this physics problem because I don't really understand all the components of the problem: A 7.25 kg block is sliding at 5.45m/s on a frictionless lab bench which is 8.6m high. The block hits a 1m "rough patch" before sliding off of the lab bench, and then lands...
44. ### 2D Kinematics questions -been stuck fo hours on it

Homework Statement Okay so here is the problem: A golf ball is struck and leaves the ground at 96 m/s on a 60 angle. Determine the velocity of the ball 2 seconds after it was struck. I have the answer provided, which is 32.6 m/s at 45° above the horizon. Homework Equations Obviously I...
45. ### How Can Physics Predict the Danger Zone for Plants from Falling Snow?

Homework Statement So...In Central Oregon there is a winter time problem that is troublesome to gardeners having to do with large masses of snow sliding off the roof and crushing plants and shrubs on the ground. Physics (in particular 2-D Kinematics) allows us to determine some features of...
46. ### Linking two vectors in 2D kinematics

Homework Statement You're a pilot beginning a 1000- flight. Your plane's is 1200 , and air traffic control says you'll have to head 15 west of south to maintain a southward course. If the flight takes 90 minutes what is the winds velocity (vx, vy?) Homework Equations delta r = (bx-ax...
47. ### Can somebody help translate this question? 2D Kinematics.

I'm having difficult understanding the question, can somebody help me? The question is: "The velocity of a 3 kg particle is given by v = (3ti + 6(t^2)j )m/s, with time t in seconds. At the instant the net force on the particle has a magnitude of 35 N, what are the direction (relative to the...
48. ### Objects Flying towards each other (2d kinematics)

Homework Statement A cat and a baby are launched from skeet traps on opposite sides of the Grand Canyon, which are at the same height and a distance ℓ apart. The cat is launched horizontally at speed (v0/√2), the baby at initial speed v0 at an angle of (pi/4) above the horizontal. By amazing...
49. ### 2D Kinematics; Flying Saucer observed with two velocities

Homework Statement A flying saucer maneuvering with constant acceleration is observed with the positions and velocities shown below: http://imgur.com/gq1g0 What is the saucer's acceleration? *note: I created the image in paint and I did forget to label the vectors. The one starting...
50. ### 2D Kinematics - Finding Initial Velocity

Homework Statement The "hang time" of a punt is measured to be 3.50 s. If the ball was kicked at an angle of 69.0° above the horizontal and was caught at the same level from which it was kicked, what was its initial speed? (Neglect air resistance.) Homework Equations All Kinematics...