PLEASE HELP it takes tsooo long! lol ima fail! please help! thanks!

A 13.0 kg wheel, essentially a thin hoop with radius 1.80 m, is rotating at 469 rev/min. It must be brought to a stop in 16.0 s.

Stella [2.4K]

Answer:

Explanation:

Given

mass of wheel m=13 kg

radius of wheel=1.8 m

N=469 rev/min

$\omega =\frac{2\pi \times 469}{60}=49.11 rad/s$

t=16 s

Angular deceleration in 16 s

$\omega =\omega _0+\alpha \cdot t$

$\alpha =\frac{\omega }{t}=\frac{49.11}{16}=3.069 rad/s^2$

Moment of Inertia $I=mr^2=13\times 1.8^2=42.12 kg-m^2$

Change in kinetic energy =Work done

Change in kinetic Energy $=\frac{I\omega ^2}{2}-\frac{I\omega _0^2}{2}$

$\Delta KE=\frac{42.12\times 49.11^2}{2}=50,792.34 J$

(a)Work done =50.79 kJ

(b)Average Power

$P_{avg}=\frac{E}{t}=\frac{50.792}{16}=3.174 kW$

7 0

3 years ago

Debido al desorden en el laboratorio un científico tiene 2 termómetros diferentes pero no sabe en qué escalas están por lo que d

just olya [345]

Answer:

La escala del termómetro ''A'' es grados Celsius.

La escala del termómetro ''B'' es grados Fahrenheit.

Explanation:

Para hallar en qué escalas están los termómetros partimos de que la mezcla a la cuál se midió su temperatura mantuvo su temperatura constante.

Esto quiere decir que los termómetros están expresando la misma temperatura pero en una escala distinta.

Sabemos que dada una temperatura en grados Celsius ''C'' si la queremos convertir a grados Fahrenheit ''F'' debemos utilizar la siguiente ecuación :

$F=(\frac{9}{5})C+32$ (I)

Ahora, si reemplazamos y asumimos que la temperatura de 18° es en grados Celsius, entonces si reemplazamos $C=18$ en la ecuación (I) deberíamos obtener $F=64.4$ ⇒

$F=(\frac{9}{5}).(18)+32=32.4+32=64.4$

Efectivamente obtenemos el valor esperado. Finalmente, corroboramos que la temperatura del termómetro ''A'' está medida en grados Celsius y la temperatura del termómetro ''B'' en grados Fahrenheit.

6 0

2 years ago

When the frequency of an ac circuit is decreased, the current in the circuit increases. which combination of elements is most li

zaharov [31]

Answer:

The combination of elements most likely to comprise the circuit are resistor, inductor and capacitor

Explanation:

The impedance of an LCR circuit shown as

Z = √R² + (X↓l - X↓c)²

Z = √R² + (2π∨L - 1/2π∨c)²

Variation of Z with respect to υ is shown in the figure.

As υ increases, Z decreases and so the current increases.

At υ = υ↓r

Z is minimum, current is maximum. Beyond

υ = υ↓r

Z increases and so current decreases.

so the combination of circuit elements that is most suitable to comprise

the circuit is R, L and C.

To learn more about these circuits

brainly.com/question/13140756

#SPJ4

5 0

2 years ago

4. Lead has a density of 11.5g/cmº. A rectangular block of lead measures 7cm x5cmx2cm.

lisov135 [29]

Answer:

(a) 70cm³

(b) 805 grams

Explanation:

(a) V = L×B×H

= 7cm×5cm×2cm

= 35cm×2cm

= 70cm³

(b) Mass = Volume × Density

= 70cm³ × 11.5g/cm³

= 805 grams

3 0

3 years ago

What form of matter is vapor?

katrin [286]

The form of matter that is vapor is a gas made of a substance that is usually liquid.
Vapor is created when water, or some other liquid evaporates - meaning that it becomes so hot in a room, or wherever, that the liquid starts becoming gas.

5 0

2 years ago