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.
Explanation:
velocity = wavelength × frequency
3×10⁸ = 400/10⁹ × frequency
frequency = 3 × 10¹⁵ /400
frequency = 75×10¹¹Hz
D^2 = p^2 + q^2 - 2 pq cos D
d^2 = (4.24)^2 + (4.24)^2 - 2. (4.24) (4.24) cos 68
d^2 = 2 (4.24)^2 - 2. (4.24) (4.24) cos 68
d = 4.74
so the answer will be letter. C
hope this helps
The question isn't clear enough, I think it ask us to calculate the linear speed of a point at the edge of the DVD.
Now let's imagine we're a point at the edge of the DVD, we're undergoing a circular motion. Each minute we will complete a circular track 7200 times, now we need to know the distance we travel each turn. The perimeter of the DVD, a circular object is:

Know recall that:

We now need to know how much distance is traveled during a minute or 60 seconds:

Finally we divide this result with t=60 seconds:


Where the distance units were named units as the length unit is not specified in this exercise.<span />
Answer:
true
Explanation:
Newton is the measure of the force with turns to be gravity multiplying the mass. Thus, the forces acts on the particles in the direction of the movement of the particles