Answer:
1.8 s
Explanation:
Potential energy = kinetic energy + rotational energy
mgh = ½ mv² + ½ Iω²
For a thin spherical shell, I = ⅔ mr².
mgh = ½ mv² + ½ (⅔ mr²) ω²
mgh = ½ mv² + ⅓ mr²ω²
For rolling without slipping, v = ωr.
mgh = ½ mv² + ⅓ mv²
mgh = ⅚ mv²
gh = ⅚ v²
v = √(1.2gh)
v = √(1.2 × 9.81 m/s² × 4.8 m sin 39.4°)
v = 5.47 m/s
The acceleration down the incline is constant, so given:
Δx = 4.8 m
v₀ = 0 m/s
v = 5.47 m/s
Find: t
Δx = ½ (v + v₀) t
t = 2Δx / (v + v₀)
t = 2 (4.8 m) / (5.47 m/s + 0 m/s)
t = 1.76 s
Rounding to two significant figures, it takes 1.8 seconds.
Answer:
it would take him 1 minute to run 304.5 meters and 1 second to run 5.075 meters
Explanation:
This question is a very good one indeed! I am very happy you asked it. I would first like to say that, although energy is important, our planet is more so. That is why I feel like we should always try to explore ideas that are both useful to the human race but also useful in protecting our environment because what is the use in having energy if we will not be able to use it. That is why I feel that we should try at types of energy like solar and wind. The problem is finding ways that are less expensive and more efficient. For example, creating a wind energy system that creates a sizeable about of energy and also is not too expensive and hard to make like the wind turbines of nowadays. Also what comes into question is the effect of these ideas and I feel that although some of these may have harmful effects, they must be used. One thing though is that I do not agree in expanding on our oil and gas exploration because it has so many bad effects to our environment that it is hardly worth it. If we can find alternatives in these other sources, like many states in the USA are trying to do, then we will be able to move much faster in technology and also help protect our lovely planet.
