Jump Definition and 323 Threads

I'm sure this has been asked 1000 times before, but here's my shot: If I had a time machine and intantaneously 'jumped' 1 hour in the future, would I lose all my kinematic vector (velocity, acceleration) during my time jump? I read on another thread on PF that the Earth is moving roughly...

Homework Statement A person can jump a maximum horizontal distance (by using a 45 ◦ projectile angle) of 4 m on Earth. The acceleration of gravity is 9.8 m/s 2 . What would be his maximum range on the Moon, where the free-fall acceleration is g 6 ? Answer in units of m...

Since I last posted here, I've experimented with small DC motors, parallel and series circuits, messed with my electronic-building kit, and even did a little Job Shadowing (temporary internship) at a local electrical engineering place for school. I definitely want to make this into a profession...

Homework Statement A high jumper of mass 60.0 kg consumes a meal of 3.00 x 10^3 kcal prior to a jump. If 3.3% of the energy from the food could be converted to gravitational potential energy in a single jump, how high could the athlete jump? Homework Equations Ug = mgh gravity =...

Homework Statement Jorge is going to bungee jumpy from a bridge that is 55.0m over the river below. The bungee cord has an unstretched length of 27.0m. To be safe, the bungee cord should stop Jorge's fall when he is at least 2.00 m above the river. If Jorge has a mass of 75.0kg what is the...

Hello there! I was thinking about jumping the other day. How would one explain jumping by physics. So, before you jump, you always bend your knees. This knee bending, from my point of view shouldn't be analogized with the build up elastic energy, since the force that will cause the jump...

If I wanted to know how much force is required to jump, and I know my acceleration while jumping, would I just use F=ma. Or do I need to account for gravity, as in use Fjump - Fg = ma

I would really like to get a jump on calculus before next semester when I take calculus... The calc book that I am currently reading is ... https://www.amazon.com/dp/0486404536/?tag=pfamazon01-20 . I want another calc book to read to. I don't want calculus for dummies or any book like that... I...

Correct me if I am wrong, but atoms emit photons when they jump energy levels. Right?

When the electrons in silicon are excited by visible light and jump into the conduction band how do the electrons replace? So for example, wouldn't a solar cell only last for so long if all the valence electrons are excited and converted into current. I am looking at it as if all the valence...

1.A lazy flea approaches a stationary log with radius R. At what distance from the log must the flea be to jump over the log with the least amount of effort. Hint: Plot Velocity versus the angle. 2.(Not sure how I should type these) I plan to use constant acceleration projectile motion...

Homework Statement Julie has a mass of 60 kg. In an experiment she crouched down, then jumped straight up. Her lab partners measured the height of her center of mass above the floor at three instants: 1) 0.43 m when crouched down; 2) 1.02 m just as her feet were leaving the floor; 3) the...

Homework Statement The triple jump is a track-and-field event in which an athlete gets a running start and tries to leap as far as he can with a hop, step, and jump. Shown in the figure is the initial hop of the athlete. Assuming that he approaches the takeoff line from the left with a...

Speed --- the bus jump in the movie! Homework Statement In the movie Speed1, a loaded city bus is rigged with an explosive that will detonate and kill everyone aboard if its speed goes below 50 miles per hour. As the bus is moving, the people on board are informed that a bridge ahead in the...

Homework Statement A Locust can jump as far as 75 cm horizontally, given a 55° angle above horizontal, what is the initial velocity? Given: d=75cm (0.75m) Angle=55° Homework Equations a= v/t d=vt The Attempt at a Solution t = (v)sin55 / 9.81 t = 0.75 / (v)cos55 t = t...

Homework Statement estimate the velocity you achieve when you jump straight up hint use the height you reach jumping on Earth to estimate the change in potential energy and then use conservation of energy to estimate you initial kinetic energyHomework Equations ymax=(v^2 sin^2 @)/2g The...

Homework Statement In the vertical jump, an athlete starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat the athlete as a particle and let Y(max) be his maximum height above the floor...

Me and a friend at school have been thinking about this question for a while and have come up with a few perspectives, I'm sure there's a 'proper' answer but I haven't managed to find one even after scouring numerous web pages. We are aware that the electron doesn't 'move' in a sense, only the...

Hi I'm a complete n00b at calculus (first day of the first year) so this question may appear a little...stupid. But I want to hammer into my head every little thing I hear in the lecture hall, so I might as well give it a go. Today the professor explained how jump discontinuities must be...

Is it possible for electricity to jump a vacuum gap? If so, what is it called when that happens?

Currently medical physicists especially fresh graduates are experiencing difficulty in landing jobs. But the future is bright, think about the population ages. If you enroll in med phys now, after 5 years (assume MSc and residency) the market will be back, and you will have a good career.

It is said that jumping with the Fosbury Flop technique, one's center of mass stays significantly under the bar. What if, instead of the bar, one tryed to jump over a wall? It looks as though there's no difference between the bar and the wall, but the wall is a potential barrier for the center...

1. Homework Statement A ski jumper leaves the end of the slope, make a 35º with the horizontal and the slope making -45º with the horizontal. it has initial velocity of 8m/s. For him not to fall the tangent of the trajectory and the slope at the moment of impact should not be bigger then 20º...

Hi there, I'm interested in the force required to jump. It's been a decade since physics, my old copy of Serway is 1,000 miles away, and I can't remember enough about solving the problem to put proper keywords into a Google search (yeah, it's pathetic). I remember enough about Newtonian...

Hi, do you jump higher when you run and jump, or just stand and jump? I believe you jump higher if you run and jump.

I've been bothered by this question. Say we have an electron in it's ground state. According to quantum mechanics, that is a stationary state. Then we excite the atom and the electron jumps into a higher energy level. That is also a stationary state. The question is: Why does the electron jump...

The girl is going on a bungee jump. She weighs 65 kg. The rope is 11m. In total, she fell 36 m. The first 11 m is free fall, and another 25m is simple harmonic motion. 1) k of rope 2)max spped 3)what point when she has max speed 4)amplitude of rope 5)how long does it take Homework...

Homework Statement A Year 12 Physics student has a mass of 85kg and is planning to bungee jump from a 200m high tower with a Killer Python Snake strapped to his ankles. The student decides to place his life in your hands and will totally rely on your knowledge of physics. He requests you to...

You go bungee jumping from a bridge that is 65m high, the bungee cord has an unstretched length of 32m and a spring constant of k=107 N/m You have a mass of 75kg. Question: what is the acceleration at the bottom, closest to the ground? I`ve tried to use 1/2kA2=1/2mx+1/2kx2 but it...

A 48 kg skier starts from rest at a height of H = 28 m above the end of the ski-jump ramp. As the skier leaves the ramp, his velocity makes an angle of 28° with the horizontal. Neglect the effects of air resistance and assume the ramp is frictionless. Could u give me a formula i need to start...

How much force is needed for "Super Jump Shoes"? My goal is to build a pair of super jump shoes. The road may be tough, but I like things to be tough. I was wondering how much force i would need for them to hit the ground to make at least a 180lbs/80kg person jump at least 1 foot in the air...

I've taken enough math courses that it would actually be easier for me to get a BS in math, with a minor in physics, rather than a BS in physics and a minor in math (like I had thought I might like to do originally). My question is, could I pursue a MS in physics in grad school if I go ahead...

Hello, I am trying to prove the following... lim (x+3) \left|x+5\right|/x+5 x\rightarrow-5 from the left, L=+2 from the right, L=-2 I used delta-epsilon on the right hand limit and got \delta = \epsilon However, I'm not sure how to proceed when I get to this step while trying to prove the...

Homework Statement A skier (m=53.00 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally. If h = 8.00 m and D = 9.50 m, find H. http://img517.imageshack.us/img517/616/prob21a.gif Homework Equations .5mv^2+mgh=.5mv^2+mgh The Attempt...

Six men with machine guns at the Grand Hyatt. A few injuries but nothing serious. All I can say is wow. http://www.nypost.com/p/news/international/brazen_bandits_hold_up_big_berlin_MLl35Q0NFMNR06LBaGmQnM Live broadcast video and bystander video...

What is the "jump condition"? I've been studying Green's function and I've come across something called the "jump condition". What is the "jump condition" and what it is used for (and perhaps an example)? Cheers.

Homework Statement A 98.6 kg basketball player can leap straight up in the air to a height of 98.2 cm, as shown below. The player bends his legs until the upper part of his body is dropped by 67.0 cm, then he begins his jump. With what speed must the player leave the ground to reach a height...

http://i48.tinypic.com/wt8094.jpg how to deside which voltage or current is continues ?

When a bungee jumper reaches the lowest point of their jump, is the direction of acceleration up or down? What about at the highest point?

Homework Statement This is a semester review. I am having trouble starting the second part of this question. It is well-know fact that Superman is "faster than a speeding bullet, more powerful than a locomotive, and able to leap tall buildings in a single bound." Assume his mass is 100kg. The...

Homework Statement An Exceptional standing jump would raise a person 0.80m off the ground. To do this, what force must a 66Kg person exert against the ground? Assume the person crouches a distance of 0.20m prior to jumping, and thus the upward force has this distance to act over before he...

In the movie Speed a speeding bus is shown jumping a long gap in the elevated freeway. The Mythbusters test the physics at 1/12 scale. In the TV show Grant writes an equation to find the scaled down ramp exit velocity, where supposedly one must compensate the small scale speed downward because...

Homework Statement an 80Kg bungee jumper steps off the jump platform which is 50m above the ground. the bungee cord is 25m long when relaxed and has an E value of 8 MPa and a cross sectional area of 400mm^2. Calculate the closest the jumper gets to the ground. Consider the center of...

Hi, I was wondering if the act of jumping itself has an effect on the ball as it is released out of the players hands(ex. momentum etc.). I know that the increased height decreases the chance of the ball from being blocked, but i was wondering if it does more than that. Thank You

Homework Statement At what speed would a 70-kg high jumper have to leave the ground in order to raise his body up to a height of 1.60 m Acceleration due to gravity: 9.8 m/s^2 [down] Homework Equations Kinetic Energy = 0.5(mass)(velocity^2) Gravitational Potential Energy =...

I'm working on a problem that analyzes vertical jump kinetics. I have a data file that has force plate data and corresponding time steps when a person jumped straight up and then landed on a force plate. I also have the vertical distance that the person jumped. I want to calculate: 1. The...

The question asks to describe in terms of physics how basketball players can jump straight up into the air. I also have to show free body diagrams of the forces on the ground and on the player. The basketball player has gravity and normal forces acting on him and I am assuming that the rest...

Homework Statement A runner jumps at 30 degrees to the ground and covers 8.90 m. What was the takeoff speed? The Attempt at a Solution I have no idea where to start...

Homework Statement f(x) = -x + b, if x < 2 = 5, if x = 2 = -20/(x-b) + 1, if x > 2 For what value(s) of b does f have a removable discontinuity at 2? For what value(s) of b does f have a (finite) jump discontinuity at 2? Write your answer in interval notation. The Attempt at a...

Homework Statement During a high school track meet, an athlete performing the long jump runs and leaps at an angle of 25 degrees and lands in a sand pit 8.8 m from his launching point. If the launch point and landing point are at the same height, y=0m, with what apeed does the athlete land...