Would you expect the density of graphite and diamond to be the same

A DJ starts up her phonograph player. The turntable accelerates uniformly from rest, and takes t1 = 11.9 seconds to get up to it

Degger [83]

Answer:

a) $\omega_1=8.168\,rad.s^{-1}$

b) $n_1=7.735 \,rev$

c) $\alpha_1 =0.6864\,rad.s^{-2}$

d) $\alpha_2=4.1454\,rad.s^{-2}$

e) $t_2=1.061\,s$

Explanation:

Given that:

initial speed of turntable, $N_0=0\,rpm\Rightarrow \omega_0=0\,rad.s^{-1}$

full speed of rotation, $N_1=78 \,rpm\Rightarrow \omega_1=\frac{78\times 2\pi}{60}=8.168\,rad.s^{-1}$

time taken to reach full speed from rest, $t_1=11.9\,s$

final speed after the change, $N_2=120\,rpm\Rightarrow \omega_2=\frac{120\times 2\pi}{60}=12.5664\,rad.s^{-1}$

no. of revolutions made to reach the new final speed, $n_2=11\,rev$

(a)

∵ 1 rev = 2π radians

∴ angular speed ω:

$\omega=\frac{2\pi.N}{60}\, rad.s^{-1}$

where N = angular speed in rpm.

putting the respective values from case 1 we've

$\omega_1=\frac{2\pi\times 78}{60}\, rad.s^{-1}$

$\omega_1=8.168\,rad.s^{-1}$

(c)

using the equation of motion:

$\omega_1=\omega_0+\alpha . t_1$

here α is the angular acceleration

$78=0+\alpha_1\times 11.9$

$\alpha_1 = \frac{8.168 }{11.9}$

$\alpha_1 =0.6864\,rad.s^{-2}$

(b)

using the equation of motion:

$\omega_1\,^2=\omega_0\,^2+2.\alpha_1 .n_1$

$8.168^2=0^2+2\times 0.6864\times n_1$

$n_1=48.6003\,rad$

$n_1=\frac{48.6003}{2\pi}$

$n_1=7.735\, rev$

(d)

using equation of motion:

$\omega_2\,^2=\omega_1\,^2+2.\alpha_2 .n_2$

$12.5664^2=8.168^2+2\alpha_2\times 11$

$\alpha_2=4.1454\,rad.s^{-2}$

(e)

using the equation of motion:

$\omega_2=\omega_1+\alpha_2 . t_2$

$12.5664=8.168+4.1454\times t_2$

$t_2=1.061\,s$

4 0

3 years ago

The magnetic field produced by a long straight current-carrying wire is

alexdok [17]

Answer:

proportional to the current in the wire and inversely proportional to the distance from the wire.

Explanation:

The magnetic field produced by a long, straight current-carrying wire is given by:

$B=\frac{\mu_0 I}{2 \pi r}$

where

$\mu_0$ is the vacuum permeability

I is the current intensity in the wire

r is the distance from the wire

From the formula, we notice that:

- The magnitude of the magnetic field is directly proportional to I, the current

- The magnitude of the magnetic field is inversely proportional to the distance from the wire, r

Therefore, correct option is

proportional to the current in the wire and inversely proportional to the distance from the wire.

8 0

3 years ago

An object to charge 2.00 c is a pretty from a second object with the same charge by a distance of 1.50 m what is the electric fo

Orlov [11]

F = q₁q₂C / r²

F force
q charge
C Coulomb constant
r separation between charges

5 0

3 years ago

URGENTTT PLEASE HELPPPP. You put m1 = 1 kg of ice cooled to -20°C into mass m2 = 1 kg of water at 2°C. Both are in a thermally i

STatiana [176]

Answer:

Explanation:

heat lost by water will be used to increase the temperature of ice

heat gained by ice

= mass x specific heat x rise in temperature

1 x 2090 x t

heat lost by water in cooling to 0° C

= mcΔt where m is mass of water , s is specific heat of water and Δt is fall in temperature .

= 1 x 2 x 4186

8372

heat lost = heat gained

1 x 2090 x t = 8372

t = 4°C

There will be a rise of 4 degree in the temperature of ice.

5 0

3 years ago

What are three ways that you know an object has accelerated

ivann1987 [24]

An object has undergone acceleration if ...

-- it's moving faster than it was before
or
-- it's moving slower than it was before
or
-- it's moving in a different direction that it was before.

3 0

3 years ago