Kinetic Energy and Work
Jun 29, During a physics unit, have students explore potential and kinetic energy with these five fun experiments that encourage problem solving and. Aug 2, Explore The Physics Classroom's board "Work and Energy" on Pinterest. | See more ideas about Work and energy, Gravitational potential energy and Kinetic energy. an understanding of work and its relationship to energy to analyze numerous Nursing Memes That Will Definitely Make You Laugh. Kinetic energy is a scalar. The units are the same as for work (i.e. Joules, J). Relation bewteen KE and W: The work done on an object by a net force equals the.
And what's interesting is-- I mean if you want to think of an exact situation, imagine an elevator that is already moving because you would actually have to apply a force slightly larger than the acceleration of gravity just to get the object moving. But let's say that the object is already at constant velocity.
Let's say it's an elevator. And it is just going up with a constant velocity. And let's say the mass of the elevator is-- I don't know-- 10 kilograms. And it moves up with a constant velocity. It moves up meters. So we know that the work done by whatever was pulling on this elevator, it probably was the tension in this wire that was pulling up on the elevator, but we know that the work done is the force necessary to pull up on it.
Well that's just going to be the force of gravity. So we're assuming that the elevator's not accelerating, right?
Because if the elevator was accelerating upwards, then the force applied to it would be more than the force of gravity. And if the elevator was accelerating downwards, or if it was slowing down upwards, then the force being applied would be less than the acceleration of gravity. But since the elevator is at a constant velocity moving up, we know that the force pulling upwards is completely equal to the force pulling downwards, right?
Because gravity and this force are at the same level, so there's no change in velocity. I think I said that two times. So we know that this upward force is equal to the force of gravity. At least in magnitude in the opposite direction. So this is mg. Times the acceleration of gravity. Let's say that's 9.
Exploring Potential and Kinetic Energy
I'm not writing the units here, but we're all assuming kilograms and meters per second squared. And we're moving that for a distance of meters. So how much work was put into this elevator, or into this object-- it doesn't have to be an elevator-- by whatever force that was essentially pushing up on it or pulling up on it? And so, let's see. This would be 98 times So it's 9, Newton meters or 9, joules. After we've moved up meters, notice there's no change in velocity.
Work and energy (part 2) (video) | Khan Academy
So the question is, where did all that work get put into the object? And the answer here is, is that the work got transferred to something called potential energy. And potential energy is defined as-- well, gravitational potential energy.
We'll work with other types of potential energy later with springs and things. Tape ends of stick to bottoms of two of your cups. Ramps, Angles and Measuring Integrate math and science by constructing ramps. Kids use blocks or other materials on hand to construct their ramps.
Exploring Potential and Kinetic Energy - WeAreTeachers
Make sure all ramps are made with the same materials for accurate results. You will need to secure your ramps with duct tape. Kids investigate how different angles can affect the speed and distance of a ball.
Before you test out your ramps, have kids make a prediction. Which ramp do they think will make the ball go the farthest and the fastest? Younger kids can compare their ramps by the number of blocks holding it up example above: Which ramp helped the ball travel the farthest distance?
Work and energy (part 2)
Instantaneous power is work performed over time period that is approaching zero. Power measures speed with which work is performed. What is the optimum gear ratio for cycling as fast as possible under the given conditions? What is the optimum length of step to walk as fast as possible under the given conditions? To answer these complicated questions it will help us to know the concept of power and also to know certain qualities of muscles.
That could mean that the best gear ratio in cycling is not the top, neither the bottom, but somewhere between the both extremes.
The optimum length of step in running is not the longest, neither the shortest but somewhere in between. The best choice of gear ratio, length of step, etc.
The force with which the weightlifter acts on the barbell and the velocity of his motion indicates enormous muscle power about 3. If the time of motion were longer, would he still be able to produce such enormous power? Duration of physical activity substantially influences the ability to produce muscle power. Power outputs of runners at medium distances are markedly lower than that of sprinters because the duration of their motor activity is increased from one to seven minutes.