Initial velocity Definition and 458 Threads

  1. DaTario

    I Change in Momentum from mass contribution to the moving object

    Hi All, in the figure below we see two cases in which a wheelbarrow moves with speed v, containing a certain mass of water. At a given time t0 a drop of water is added to the system by a dripper. In case 1, the drop enters the system, which increases in mass, having the same speed as the cart...
  2. Kaiser98

    Projectile motion problem – determining initial velocity of throw

    My reasoning was to use this kinematic equation to first get time of flight of the baseball using horizontal components, and then use this same equation again to find initial velocity.
  3. mncyapntsi

    1D collision, varying masses but same initial velocity

    I know I need to look at the conversation of momentum, as well as the conservation of kinetic energy. However I get stuck with my equations. Any help would be greatly appreciated! I've already got (don't know where I am going wrong): (v)^2 + (1/2)(m)(v)^2 = (vf1)^2 + (1/2)(m)(vf2)^2 (3/2)v^2 =...
  4. S

    Initial velocity and angle when a ball is kicked over a 3m fence

    Hello there, I don't understand what I'm doing wrong I don't get the correct answer, but have done the same analysis 3x already and still get the same... Some input would be appreciated thanks in advance. Note: y-axis is upwards and x-axis is to the right. 3 unkowns i.e. 3eqs. ##x = x_0 +...
  5. A

    I If we throw a ball with initial velocity v0, is there a force?

    If we throw a ball with initial velocity v0, and the ball progresses in a projectile motion, ignoring air resistance, will there be a force in the x direction? If so, what is that force in the x direction's value mathematically? I know there is a force in the y direction due to gravity.
  6. rudransh verma

    B Is the final velocity of a Tossed tomato the same as its initial velocity

    When a tomato is thrown up with a velocity ##v_0## it’s kinetic energy is 1/2mv_0^2. It will stop at the top and then again comes back to the launch point where it’s kinetic energy will be same as before, 1/2mv_0^2. How is this possible? Also when we throw the tomato up how can you be so sure...
  7. Physics_learner

    Kinematics - can't find the initial velocity according to the image

    I tried to write the data I understood from the image: y0=160m yf=0 x0=0 x1=192m I tried to express the total change in time using the position over time equation on the Y direction: y(t)=y0+v0y*(t2-t1)-0.5a(t2-t1)^2 but then I stuck with 2 variables and didn't know what to do any help?
  8. A

    Finding kinetic energy and initial velocity of a cart over time

    Here's my list of variables and things to account for: m=100kg Wnc=5000J Wfriction=-500J -Kinetic energy will be doubled (though I don't know how that plays into it exactly) -I don't think there's any PE because it's on level ground My idea of what the equation might be: Wnc +1/2mv^2initial =...
  9. F

    I How to change CSpice initial velocity from an Asteroid SPK file?

    Hello, I've made a SPK file for asteroid 7482 (1994 PC1) with Horizon. I wan't to change the initial velocity with cspice, because I want to know where it will be in a future time at the speed changed. (now I'm using Newtons calc but is slow an error increases with time). This is for calculating...
  10. Iwanttolearnphysics

    Help Me Solve This Khan Academy Question: Friction and Initial Velocity

    Here's a picture of the question: This is a Khan Academy question and although I could just click on hint to find out what the answer is, I think it would be helpful to still ask this here before looking at the answer over there, so that I know what I did wrong. Thank you in advance to anyone...
  11. kara123

    Solving for Time Given Acceleration & Initial Velocity

    assuming initial velocity is 0 and we have the value for acceleration I'm unsure how to still use any of those equations because you must have a time value at least or a final velocity
  12. A

    B Why Is Initial Velocity Not Always Zero?

    There is something I don't understand. Isn't every object, if thrown, the initial velocity is zero? Please take a look at below example. Why the initial velocity in the below example is 98 ms^-1? Please explain. I also would like to ask what textbook contain a lot of basic physics example for...
  13. karush

    MHB When Will the Object Be 15 Meters Above the Ground?

    $\tiny{1.2.1}$ An object is propelled vertically upward with an initial velocity of 20 meters per second. The distance s (in meters) of the object from the ground after t seconds is $s=-4.9t^2+20t$ (a) When will the object be 15 meters above the ground? $15=-4.9t^2+20 \implies -4.9t^2 =-5$ ok...
  14. brotherbobby

    Maximum range on ground for an elevated cannon

    I sketch a diagram for the problem and show it to the right. My approach is going to be along the following lines : (1) Use the equation of motion in the ##x## direction to express the total time of flight ##T## as a function of the range and initial angle ##T = T(R, \theta_0)##. (2) Plug this...
  15. duchuy

    Determine initial velocity of a vertical throw

    Hi, I was given this problem saying that a ball is thrown vertically up in the air and returns to its initial position after 4 seconds. The acceleration due to gravity is given to be equal to 10m/s^2. I tried to attempt this problem by using the equation : v^2 - v0^2 = 2ah by considering...
  16. D

    Quickest Route Between Horizontal Points using the Initial Velocity & Friction

    re: https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421205 https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421230 Would it be possible to find t and r via the exact same equations as found in posts #4 and #10, and then find the...
  17. D

    Brachistochrone Problem w/ Initial Velocity

    Hello, There is a physics problem called the Brachistochrone problem which I know has been solved for 0 initial velocity (assumes 0 friction and only gravity) and I know the answer is a cycloid. My question is: is there is an existing formula for finding the portion of a cycloid which is the...
  18. peace

    Estimate the initial velocity of the cars after the collision

    What came to my mind for this question is: Consider one of the cars. The velocity and mass of this car are V and M respectively. And the velocity and mass of the piece attached to the car are m, v respectively. Before the collision, the velocity of this piece relative to this car is zero. So its...
  19. jamiebean

    The final velocity = initial velocity + acceleration x time

    I first calculated initial velocity: √7.09^2+1.07^2=7.17028 acceleration=√7.22^2+2.47^2= 7.63 then i substituted all values into this equation: final velocity=initial velocity + acceleration x time so, final velocity=82.0285 so the magnitude= final velocity-initial velocity= 74.858271 is...
  20. iamcgettigan

    How do you find the initial velocity of a projectile given angle/distance?

    I tried resolving the information given into vertical and horizontal components. I then tried to find time, as this is how I would find the initial velocity. However, I am unsure of how to use the angle in this problem to help solve it. I am also unsure of how to find the initial velocity only...
  21. L

    Initial velocity given time and angle

    From Ball 1 I can can determine it's initial velocity and then maximum height. I'm not sure how this is relevant, as I cannot find a formula using angle, time, height and velocity. I have found h=V(squared) x sin (squared) Theta / 2g and also t=2Vsin Theta/g. These give similar, but different...
  22. wicker558

    Object thrown at an angle: Initial velocity has to equal speed at t

    My solution is very sketchy, but we want the math right. However, I've came to 2 thoughts that helped me get to the solution, and those are: The only way that you can launch a ball at a velocity and have it be the same velocity two seconds later, is if it's already reached its maximum height...
  23. K

    Closest approach from initial velocity and impact parameter

    Here were my assumptions: Energy and angular momentum are both conserved because the only force acting here is a central force. The initial angular momentum of this particle is ##L = mv_0b## and we can treat E as a constant in the homework equation given above. I solved for the KE (1/2 mv^2) in...
  24. karush

    MHB Cp2.63 find the initial velocity

    cp2.63. The acceleration of a particle is given by $$a(t)=-2.00 \, m/s^2 +3.00 \, m/s^3.$$ a. find the initial velocity $v_0$ such that the particle will have the same x-coordinate at $t=4.00\, s$ as it had at $t=0$. b. What will be the velocity at $t=4.00 s$ ok sorry but I don't even know...
  25. pluralangel

    seeking help finding the initial velocity of a type 3 projectile

    hi, so I've been trying to find the initial velocity of this projectile; but i ended up getting a negative value for seconds squared. I've gone over my solution multiple times but don't see where i went wrong. alternatively, was i supposed to take the absolute value of seconds squared? thanks...
  26. Josh chips

    Find the initial velocity of the second stone

    since the question states they hit the ground at the same time i firs find the time they hit the ground y= ut + 1/2at^2 initial velocity is 0 for the first stone 320= 0 + 4.9t^2 this t= 8 secs since the 2nd stone was thrown 100 m below stone 1 distance from ground is 220m 220 = ut -...
  27. T

    How to find initial velocity with only an angle and distance?

    I am in Algebra 2 and the homework asks a question: "You and a friend arw driving golf balls at a driving range. If the angle of elevation is 30 degrees and the ball travels 625 feet horizontally, what is the initial velocity of the ball?"
  28. R

    Find the initial velocity of a water rocket (mass changes)

    Homework Statement Find the initial velocity of the boost phase (when water is coming out). Here is everything I know - Mass of rocket with no water is 0.13kg, mass of rocket with water is 1.1kg. The total length of the rocket is 0.48m. The time to the maximum point is 3.46 seconds, and total...
  29. E

    Initial velocity in an inelastic collision

    Homework Statement A drunken driver crashes his car into a parked car that has its brakes set. The two cars move off together (perfectly inelastic collision) for 6.0 m. If the mass of the moving car is 1030 kg and the mass of the parked car is 1410 kg how fast was the first car traveling when...
  30. M

    Projectile motion - determining initial velocity and angle

    Homework Statement An archer launches an arrow from coordinates ##(0, 0)## at an angle ##\alpha## and with an initial velocity ##v_0##. There's a target located ahead of the archer and the center of that target is at coordinates ##(d, h)##. At what ##v_0## and at what angle ##\alpha## does...
  31. M

    Projectile Motion: initial velocity problem

    Homework Statement Determine the initial velocity of a projectile that reuturns to launch level 10.0 seconds after it is launched and lands 300.0m away from the launch site. Homework Equations Δx=v0xt Δy=v0yt+1/2gt2 The Attempt at a Solution [/B] 300=v0x(10) v0x=30m/s I don't...
  32. K

    Finding Initial Velocity v0x for Particle with Non-Constant Acceleration

    Homework Statement Find the initial velocity v0x such that the particle will have the same x-coordinate at time t= 4.07 s as it had at t=0. The acceleration of a particle is given by ax(t)=−2.00 m/s2 +( 3.09 m/s3 )t. Homework Equations v = v0 + a t Δx = ((v+v0)/2)t Δx = v0t + 1/2at^2 v^2 =...
  33. H

    Mass going up an inclined plane with initial velocity Vo

    1. Vo Mass=m 2.So we tried two ways of doing this, one is by taking the y component of the i itial velocity and using that and the other by using the component of its weight parallel to the initial velocity.They give conflicting answers. For the left one it turns out to be t=Vosinθ/g But for...
  34. P

    Projectile Motion: Initial Velocity Derivation

    Hey guys, I am working on a school project and have fired some water rockets at different angles. I am now trying to compare theoretical results vs experimental results. But I am struggling to produce an accurate mathematical model. I have attached my attempt to this post. It is quite long and...
  35. A

    Finding initial velocity of two elementary particles

    <Moderator's note: Moved from a technical forum and thus no template.> I'm not sure how they got the extra (1/2)mv^2? My question is shown using pink font in the image below as well as my attempt.
  36. Francis Perez

    Find the Initial Velocity and Launch Angle for a Particular Trajectory

    Homework Statement Hello, so I’ve been trying to find some possible way to calculate this: The initial Velocity and angle needed to launch a projectile and reach the coordinates (x,y). The maximum height the ball can reach before it starts to head down to the target value should be y+5m The...
  37. vcm1992

    Find Initial Velocity Given Height, Range, and Initial Angle

    Homework Statement So! The problem states that a grasshopper jumps from the edge of a table. We know that x-initial is zero and x-final is 1.06m. This is how far he jumped from the origin. The height of the table is unknown, but we know that the height of the grasshoppers jump with respect...
  38. D

    A projectile's initial velocity without time?

    Homework Statement A projectile is launched: Horizontally, with an average displacement of 49 cm Vertically, with an average displacement of 28 cm At a 23 degree angle, with average displacement of 126 cm Homework Equations The Attempt at a Solution I am sad to say I don't know how to do it...
  39. D

    Initial velocity if a performer clears a 30 m tall object

    Homework Statement In 1940, Emanuel Zachinni, one of a family of “human cannonball” performers, set a world record by traveling 53m. If he clears the 20 m tall ferris wheel (which is 25 m away from the cannon) by 10 m, how fast was he going at launch? Homework Equations range 53m...
  40. B

    Initial velocity of ball B hit a free falling ball A

    Homework Statement A boy release ball A from height 5m from ground at the same time other boy throw ball B vertically upward to exactly strike ball A. When ball B released it was 1m from ground find minimum initial velocity of ball b. Given g=10m/s^2 a) 2m/s b) 3m/s c) 4m/s d) 5m/s Homework...
  41. I

    A weird velocity/acceleration question

    Homework Statement This problem showed up in my final review packet, and I /think/ it should be basic kinematics, but I don't even know how to approach it with the second half of it. An object moves according to the equation x = vt + ke^(bt), where k, v, and b are constants, x represents...
  42. C

    MHB Find Car B's Initial Velocity: A Physics Puzzle

    Dear Every one, Two cars approach an extremely icy four-way perpendicular intersection. Car A travels northward at 12 m/s and car B is traveling eastward. They collide and stick together, traveling at 40.1° north of east. What was the initial velocity of car B (in m/s)? (Enter the magnitude...
  43. M

    Relativity: Initial velocity and e/m of Thomson's experiment

    Homework Statement In an experiment similar to Thomson’s, we use deflecting plates 5 cm in length with an electric field of 1.0×10^4 V/m. Without the magnetic field, we find an angular deflection of 30°, and with a magnetic field of 8×10^-4 T we find no deflection. What is the initial velocity...
  44. G

    Find initial velocity and acceleration of a bike

    Homework Statement A power plant operator on a bicycle is pedaling at uniform acceleration of "a", when his initial velocity "u" m/s. After 6.2s, and 9.3s, the bicycle had moved 23.5m & 39.7m respectively. Find the value of "u" & "a". Homework Equations s=ut+1/2at^2The Attempt at a Solution...
  45. C

    Compressing a bottle with water - initial velocity of water

    Imagine that we have a closed plastic bottle filled with water and then we punch a hole with area A in its cap. How can I find the initial velocity the water will he "fired" with if we squeeze the bottle applying stress S? Assume that we know all about the bottle (moduli, change in volume etc...
  46. S

    Initial Velocity of a dropped object problem

    Why we take initial velocity of dropped object downwards as 0 and 25m/s when the object is thrown 25m/s upwards ? What is then initial velocity cause when t=0 both object dropping and moving upwards had 0 velocity - in other words when object came to motion at both places it had some velocity?
  47. N

    [Momentum and Energy] How much of initial velocity is lost?

    Homework Statement A 10kg block moving at 1 m/s hits another 10kg stationary block. Those two blocks (now stuck together) collide with another 10kg stationary block. What percent of the original energy is lost after the two collisions? Homework Equations m1v1 + m2v2 = (m1+m2)v3 Kinetic energy...
  48. R

    A ball is hit with initial velocity -- Find the Horiz/Vert displacement

    Homework Statement A softball is hit with an initial velocity of 29 m/s. at an angle of 60 degrees above the horizontal and impacts the top of the outfield fence 5s later. Assuming the initial height of the softball was .5 m above (level) ground, what are the balls horizontal and vertical...
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