A child looked at

A person of mass 70 kg stands at the center of a rotating merry-go-round platform of radius 2.9 m and moment of inertia 900 kg⋅m

Cloud [144]

Explanation:

It is given that,

Mass of person, m = 70 kg

Radius of merry go round, r = 2.9 m

The moment of inertia, $I_1=900\ kg.m^2$

Initial angular velocity of the platform, $\omega=0.95\ rad/s$

Part A,

Let $\omega_2$ is the angular velocity when the person reaches the edge. We need to find it. It can be calculated using the conservation of angular momentum as :

$I_1\omega_1=I_2\omega_2$

Here, $I_2=I_1+mr^2$

$I_1\omega_1=(I_1+mr^2)\omega_2$

$900\times 0.95=(900+70\times (2.9)^2)\omega_2$

Solving the above equation, we get the value as :

$\omega_2=0.574\ rad/s$

Part B,

The initial rotational kinetic energy is given by :

$k_i=\dfrac{1}{2}I_1\omega_1^2$

$k_i=\dfrac{1}{2}\times 900\times (0.95)^2$

$k_i=406.12\ rad/s$

The final rotational kinetic energy is given by :

$k_f=\dfrac{1}{2}(I_1+mr^2)\omega_1^2$

$k_f=\dfrac{1}{2}\times (900+70\times (2.9)^2)(0.574)^2$

$k_f=245.24\ rad/s$

Hence, this is the required solution.

5 0

3 years ago

220V is applied to two different conductors made of the same material. One conductor is twice as long and twice as thick as the

ollegr [7]

Answer:

Explanation:

For calculating resistance of a conductor , the formula is

R = ρ l / A , ρ is specific resistance , l is length and A is cross sectional area of wire.

For first wire length is l₁ , area is A₁ resistance is R₁, for second resistance is R₂ , length is l₂ and area is A₂

Given , l₁ = 2l₂ , A₁ = 4A₂ , area is proportional to square of thickness.

R₁ / R₂ = I₁A₂ / I₂A₁

= 2l₂ x A₁ / 4 I₂A₁

= 1 / 2

2R₁ = R₂

Power = V² / R

Ratio of power = (V² / R₁) x (R₂ / V²)

= R₂ / R₁

= 2 .

7 0

3 years ago

Before you conduct your experiment, you need to form a hypothesis. A hypothesis is a prediction of what you think will happen in

Stolb23 [73]

Example: A apple rotting.

If I put my apple in a fridge, then it would not rot as fast because it is in a cooled area. (example)

Hope it helps! Brainiest Answer would be amazing!

5 0

3 years ago

How are elements and<br> compounds identified?

irina1246 [14]

Elements are composed of single atoms and compounds are composed of different elements.

<u>Explanation:</u>

A single atom generally forms an element. It is an individual particle or atom present in the periodic table, mostly it refers with symbol. When two or more elements of different types or same types combine together, it is called as compound.

The compounds can be heterogeneous compounds and homogeneous compounds. Depending upon the combination of elements, this classification is done for compounds. The elements can form a compound by ionic, covalent, metallic or hydrogen bonding. The molecules can also be termed as compounds.

3 0

3 years ago

Which substance has the highest density at room temperature?

12345 [234]

I think phosphorus has the highest density at room temp.

6 0

3 years ago