Answer:
0.19 rev
Explanation:
We can solve the problem by using the law of conservation of angular momentum. In fact, if we assume there are no external torques acting on the diver, the angular momentum must be conserved:
where
L is the angular momentum
I is the moment of inertia
is the angular velocity
- When the diver is tucked,
is her moment of inertia
She makes 2 revolutions (so, ) in t = 1.0 s, so her angular velocity is
So her angular momentum is
- When the diver is not tucked,
The angular momentum is conserved, so
the moment of inertia is
So the angular velocity is
So in a time of t = 1.5 s, the angular displacement is
Converting into revolutions,
Answer:
Thank you :)
Explanation:
And congrats on finishing !!
2) all of their motion stops completely
Answer:
45.5 m
Explanation:
m = 2 kg, h = 20 m, E = 500 J, radius of earth = R, mass of earth = M
find the new height H
at h, the potential energy = -GMm/(R + h)
at H, the potential energy = -GMm/(R + H)
increase of the potential energy
= [-GMm/(R + H)] - [-GMm(R + h)]
= GMm[1/(R + h) - 1/(R + H)] = E
1/(R + h) - 1/(R + H) = E/(GMm)
(H - h)/[(R + H)(R + h)] = E/(GMm)
R + h ≈ R, R + H ≈ R
so (H - h)/R² = E/(GMm)
H - h = ER²/(GMm)
note GM/R² = g = 9.81 m/s²
so H - h = E/(mg)
H = h + E/(mg) = 20 + 500/(2*9.81) = 45.5 m