Answer:
7.6 s
Explanation:
Considering kinematics formula for final velocity as
Where v and u are final and initial velocities, a is acceleration and s is distance moved.
Making v the subject then
Substituting 8.8 m/s for u, 138 m for s and 2.45 m/s2 for a then
Also, v=u+at and making t the subject of the formula
Substituting 27.45 m/s for v, 8.8 m/s for u and 2.45 m/s for a then
Therefore, it needs 7.6 seconds to travel
Answer:
Explanation:
a ) Time period T = 2 s
Angular velocity ω = 2π / T
= 2π / 2 = 3.14 rad /s
Initial moment of inertia I₁ = 200 + mr²
= 200 + 25 x 2.5²
=356.25
Final moment of inertia
I₂ = 200 + 25 X 1.5 X 1.5
= 256.25
b ) We apply law of conservation of momentum
I₁ X ω₁ = I₂ X ω₂
ω₂ = I₁ X ω₁ / I₂
Putting the values
ω₂ = 4.365 rad s⁻¹
c ) Increase in rotational kinetic energy
=1/2 I₂ X ω₂² - 1/2 I₁ X ω₁²
.5 X 256.25 X 4.365² - .5 X 356.25 X 3.14²
= 684.95 J
This energy comes from work done against the centripetal pseudo -force.
Answer:
Explanation:
The law of conservation of angular momentum states that angular momentum remains constant when there is no external moment or forces applied to the system. Let assume that star can be modelled as an sphere, then:
The final angular speed is: