'First Quarter' is the phase that appears one quarter of the
period of time from one new moon to the next one.
The total period of the moon's phases is 29.53 days (rounded).
One quarter of it is (29.53 / 4) = <em>7 days 9.2 hours</em> (rounded)
Answer
given,
vertical speed of stone,v = 12 m/s
height of the cliff = 70 m
a) time taken by the stone to reach at the bottom of the cliff
We know that,
S = u t + 1/2 a t²
- 70 = 12 t - 0.5 x 9.8 t²
4.9 t² - 12 t - 70 = 0
solving the equation
t = 5.2 s (neglecting the negative value)
b) again using equation of motion
v = u + a t
v = 12 - 9.8 x 5.2
v = -38.96 m/s
ignoring the negative sign
magnitude of velocity is equal to 38.96 m/s
c) total distance travel by the stone
vertical distance covered by the stone
v² = u² + 2 g h
0 = 12² - 2 x 9.8 x h
h = 7.34 m
to reach the stone to the same level distance travel be doubled.
Total distance travel by the stone
H = h + h + 70
H = 7.34 x 2 + 70
H = 84.7 m.
Answer:
Explanation:
a )
Time period T = 1/3 s
angular velocity = 2π / T
= 2 x 3.14 x 3
ω = 18.84 radian / s
b )
Applying conservation of angular momentum
I₁ ω₁ = I₂ ω₂
I₁ / I₂ = ω₂ / ω₁
2 = ω₂ / ω
ω₂ = 2 ω
c )
(KE)initial = 1/2 I₁ ω²
(KE)final = 1/2 I₂ ω₂²
= 1/2 (I₁ / 2) (2ω)²
= I₁ ω²
c )
Change in rotational kinetic energy
= I₁ ω² - 1/2 I₁ ω²
= + 1/2 I₁ ω²
d )
This energy comes from the work done by centripetal force which is increased to increase the speed of rotation.
Answer:
Time= t= 1.67 secs
Explanation:
Time= t=?= 1.67 secs
Initial Velocity= Vi = 2m/s
Final Velocity= Vf = 4m/s
Average Acceleration= av= Vf-Vi/t
Putting the values : 1.2m/s²= 4-2/t
Rearranging: t= 2/1.2= 1.67 secs
