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4 years ago

How is heat converted into work in a steam engine?

1 answer:

8 0

In an extremely simplified explanation,
What happens is that the steam (heat) that is generated by the burning of coal is used to rotate the motor of the steam engine.

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Dario, a prep cook at an Italian restaurant, spins a salad spinner and observes that it rotates 20.0 times in 5.00 seconds and t

BabaBlast [244]

Answer:

$-\frac{8\pi}{3}rad/s^2$

Explanation:

To solve this problem we need to apply the concept related to Angular Acceleration. We can find it through the equation

$\omega_f^2-\omega_i^2=2\alpha\theta$

Where for definition,

$\omega_i = \frac{\theta}{t}$

The number of revolution $(\theta)$ was given by 20 times, then

$\omega_i = \frac{20*2pi}{5}$

$\omega = 8\pi rad/s$

We know as well that the salad rotates 6 more times, therefore in angle measurements that is

$\theta = 6*2\pi rad = 12\pi rad$

The cook at the end stop to spin, then using our first equation,

$0-8\pi = 2\alpha (12\pi)$

re-arrange to solve $\alpha$ ,

$\alpha = \frac{-8\pi}{2*12\pi}$

$\alpha = -\frac{8\pi}{3}rad/s^2$

We can know find the required time,

$\omega_f-\omega_i = \alpha t$

Re-arrange to find t, and considering that $\omega_f=0$

$t= \frac{\omega_i}{\alpha}$

$t=\frac{-8\pi}{-8\pi/3}$

$t=3s$

Therefore take for the salad spinner to come to rest is 3 seconds with acceleration of $-\frac{8\pi}{3}rad/s^2$

6 0

3 years ago

Read 2 more answers

3.1 * Consider a gun of mass M (when unloaded) that fires a shell of mass m with muzzle speed v. (That is, the shell's speed rel

kramer

Answer:

$v_s=\frac{v}{1+\frac{m}{M} }$

Explanation:

Let the shells speed with respect to ground be $v_s$

Let the shells speed with respect to ground be $v_g$

mass of shell, $m$

mass of gun, $M$

The relative velocity of shell with respect to a free unconstrained gun, $v$

According to the Newton's third law of motion the direction of the velocity of gun and shell will be in the opposite direction.

So, the relation between the relative velocity and their individual velocity will be:

$v=v_s+v_g$ ......................(1)

<u>And according to the conservation of momentum (as the condition is very close to the elastic collision):</u>

$M.v_g-m.v_s=0$

substitute the value of $v_g$ from equation (1)

$M\times (v-v_s)=m\times v_s$

$M.v-M.v_s=m.v_s$

$M.v=M.v_s+m.v_s$

$v_s=\frac{M.v}{(M+m)}$

$v_s=\frac{v}{(\frac{(M+m)}{M}) }$

$v_s=\frac{v}{1+\frac{m}{M} }$

5 0

3 years ago

What effect does an u balanced force have on an object?

Free_Kalibri [48]

Effect of balanced force'
*net force is zero
*no change in shape
*no change in size
*equal and opposite force

6 0

3 years ago

A roof tile falls from rest from the top of a building. An observer inside the building notices that it takes 0.28 s for the til

PIT_PIT [208]

Answer:0.246 m

Explanation:

Given

height of window (h)=1 m

Time to pass window =0.28 s

Let roof is at a distance of $h_0$ above window

let t be the time to cover $h_0$

$h_0+1=\frac{g(t+0.28)^2}{2}$ ------1

$h_0=\frac{gt^2}{2}$ --------2

subtract 1 & 2

$1=\frac{g(t+0.28)^2}{2}-\frac{gt^2}{2}$

$1=\frac{g}{2}\left [ \left ( 2t+0.28\right )\left ( 0.28\right )\right ]$

t=0.224 s

$h_0=\frac{9.8\times 0.224^2}{2}$

$h_0=0.246 m$

5 0

3 years ago

One deterrent to burglary is to leave your front porch light on all the time. If your local power utility sells energy at 17¢ pe

Natali [406]

To be honest with you, there's not enough information here to calculate
the answer, because we don't know the power consumption of the front
porch light. The best we can do is represent that as a variable ... pick a
catchy name for it, which will show up in the final answer, and then you
can 'plug in' (get it ?) whatever size light bulb you want to use over the
front porch.

OK. First we have to give it a name. I could use a single letter, but
that's what everybody else always does. Remember ... this is going to
represent the power (watts) consumed by the front porch light when it's
turned on. It's the symbol that means "Front Porch Light Power" wherever
you see it. I could easily call it x or y or z, but I'm going to call it " FPLP ".

OK. FPLP = power consumption of the light, in watts .

0.001 FPLP = power consumption of the light, in kilowatts (kW).

(1 week) · (7 day/week) · (24 hour/day) = 168 hours .

Energy = (power) · (time) = (0.001 FPLP) · (168 hr) = 0.168 FPLP kWhours

Cost = ($0.17 per kWh) · (number of kWh) = (2.86¢) · (FPLP) .

There it is !

For an example, if you use a 100-W bulb in the front porch light,
then FPLP=100 W. If you leave it on 24/7 for a whole week, then
it's going to cost

(2.86¢) · (FPLP) = (2.86¢) · (100 W) = $2.86

6 0

3 years ago