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.
Unlike charges attracting each other
The dinosaurs first appeared in the Mesozoic and the first mass extinction occurred during the Paleozoic. Moreover, humans first appeared in the Cenozoic.
<h3>The geological eras and biological events</h3>
The dinosaurs emerged during the Triassic Period of the Mesozoic Era, approximately 220-225 million years ago.
The first mass extinction occurred in the Ordovician Period (the second period of the Paleozoic Era).
The Cenozoic is the current geological Era that encompasses the last 60 million years.
Learn more about geological eras here:
brainly.com/question/1288853
