What was his average power output

Questions Physics What is the average power output of a weightlifter who can lift kg to a height of 1. Physics The maximum gauge pressure in a hydraulic lift is Physics Compared to yesterday you did 3 times the work in one third the time. To so so your power output must have been: a the same as yesterday's power output b one third of yesterday's power output c 3 times yesterday's power output physics What is the average useful power output of a person who does 5.

Science what power is expended by a weightlifter when lifting a 60kg barbell a vertical distance of 1. Physics 11th grade Squaw Valley ski area in California claims that its lifts can move people per hour. Assume an average mass per Physics A weight lifter performs a clean and jerk on kg, raising it 2 m above the ground in 1. Individual journal my answer is a.

The empire state building is near broadway, which is known as the home to many. A art galleries B theaters C banks D museums. During a workout, the football players at State U. If a typical player has a mass of kg, estimate the average power output on the. You can view more similar questions or ask a new question. Questions physics A new record for running the stairs of the Empire State Building was set on February 3, Similar Questions MATH the empire state building in new york is feet tall it has floors rounded to the nearest whole what is the height of each floor?

By how many meters would Martha have been beaten Johnny if they Math Which of the following is a statistical question? How old Physics. History Which best describes how the Age of Discovery affected religious practices of indigenous peoples in the New World? People can generate more than a horsepower with their leg muscles for short periods of time by rapidly converting available blood sugar and oxygen into work output.

A horse can put out 1 hp for hours on end. Once oxygen is depleted, power output decreases and the person begins to breathe rapidly to obtain oxygen to metabolize more food—this is known as the aerobic stage of exercise.

If the woman climbed the stairs slowly, then her power output would be much less, although the amount of work done would be the same.

Determine your own power rating by measuring the time it takes you to climb a flight of stairs. We will ignore the gain in kinetic energy, as the above example showed that it was a small portion of the energy gain.

Figure 3. Tremendous amounts of electric power are generated by coal-fired power plants such as this one in China, but an even larger amount of power goes into heat transfer to the surroundings. The large cooling towers here are needed to transfer heat as rapidly as it is produced. The transfer of heat is not unique to coal plants but is an unavoidable consequence of generating electric power from any fuel—nuclear, coal, oil, natural gas, or the like.

Examples of power are limited only by the imagination, because there are as many types as there are forms of work and energy. See Table 1 for some examples. A tiny fraction of this is retained by Earth over the long term. Our consumption rate of fossil fuels is far greater than the rate at which they are stored, so it is inevitable that they will be depleted. Power implies that energy is transferred, perhaps changing form.

It is never possible to change one form completely into another without losing some of it as thermal energy. For example, a W incandescent bulb converts only 5 W of electrical power to light, with 55 W dissipating into thermal energy. The remainder becomes a huge amount of thermal energy that must be dispersed as heat transfer, as rapidly as it is created.

A coal-fired power plant may produce megawatts; 1 megawatt MW is 10 6 W of electric power. If the mass of the bike and the biker together is 80 kg, what must be the power output of the biker to achieve the goal? Shown below is a kg crate that is pushed at constant velocity a distance 8. The surface of the preceding problem is modified so that the coefficient of kinetic friction is decreased. The same horizontal force is applied to the crate, and after being pushed 8.

How much work is now done by the force of friction? Assume that the crate starts at rest. The force F x varies with position, as shown below. Evaluate the path integral using Cartesian coordinates.

Hint: You will probably need to consult a table of integrals. Constant power P is delivered to a car of mass m by its engine. Suppose that the air resistance a car encounters is independent of its speed.

If air resistance is proportional to speed, the car gets about 22 mpg at 34 mph and half that at twice the speed, closer to actual driving experience. Consider a linear spring, as in Figure a , with mass M uniformly distributed along its length. What is the total kinetic energy of the spring?

Hint: First express the kinetic energy of an infinitesimal element of the spring dm in terms of the total mass, equilibrium length, speed of the right-hand end, and position along the spring; then integrate.

Privacy Policy. Skip to main content. Search for:. Check Your Understanding Estimate the power expended by a weightlifter raising a kg barbell 2 m in 3 s. Show Solution W. Summary Power is the rate of doing work; that is, the derivative of work with respect to time. Alternatively, the work done, during a time interval, is the integral of the power supplied over the time interval.

Conceptual Questions Most electrical appliances are rated in watts. Show Solution Appliances are rated in terms of the energy consumed in a relatively small time interval. Show Solution The spark occurs over a relatively short time span, thereby delivering a very low amount of energy to your body. Can the power expended by a force be negative? Show Solution If the force is antiparallel or points in an opposite direction to the velocity, the power expended can be negative.

How can a W light bulb use more energy than a W oven?