A weightlifter manages to lift a 133 kg (that's 293 pounds, which sounds much more impressive) weight a distance of 1.4 m. How many kcal of heat energy is equivalent to this lift?
133 * 9.81 * 1.4 = 1826 Joules
convert that to calories and then divide by 1000 to get kilo calories (food calories)
436 calories / 1000 = .436 Kcal
This would not be an efficient way to lose weight :
To find out the amount of heat energy equivalent to lifting a weight, you can use the concept of work and energy.
The formula to calculate the work done in lifting an object is:
Work = Force × Distance × cos(θ)
Where:
- Force is the weight of the object (133 kg × gravity)
- Distance is the vertical distance the object is lifted (1.4 m)
- θ is the angle between the direction of lifting and the horizontal (usually 0° for vertical lifting)
- cos(θ) is the cosine of the angle θ (which is 1 for 0°)
First, let's convert the weight from pounds to kilograms:
1 pound = 0.453592 kg
So, 293 pounds ≈ 133 kg
Next, let's calculate the force:
Force = 133 kg × gravity
Since the weightlifter lifted the weight vertically, gravity can be approximated as 9.8 m/s^2.
Now, we can calculate the work done:
Work = Force × Distance × cos(θ)
Since θ is 0°, cos(θ) = 1.
Finally, we'll convert the work done into calories. 1 kcal (kilocalorie) is equal to 4184 Joules.
To summarize:
1. Convert the weight from pounds to kilograms: 293 pounds ≈ 133 kg.
2. Calculate the force: Force = 133 kg × gravity, where gravity ≈ 9.8 m/s^2.
3. Calculate the work done: Work = Force × Distance × cos(θ), where θ = 0°.
4. Convert the work done into kilocalories: 1 kcal = 4184 Joules.
By following these steps, you'll be able to determine the amount of heat energy (in kilocalories) equivalent to lifting the weight in question.