Ask question

Ask question

All categories

3 years ago

15

A refigerator is designed to remove 3 kW from the cold space at -10C while it rejects heat to the kitchen at 25 C. The rate of t

he reversible work is:______

1 answer:

Stells [14]3 years ago

7 0

Answer:

b

Explanation:

You might be interested in

Which of the following effects results from the interference of two sound

Natali5045456 [20]

Answer:beats

Explanation:l got it right gang

7 0

3 years ago

Jason and Guy are throwing watermelons straight up from the ground. (They’re making fruit salad.) Jason throws his watermelon at

NISA [10]

Answer:2t

Explanation:

Given

Jason throwing watermelon at speed v and it spend t time in air

time to reach max height

$v_f=u_i+at'$

0=v-gt'

$t'=\frac{v}{g}$

and time to reach bottom is also t'

t=2t'

$t=2\frac{v}{g}$

For guy throws his watermelon at speed 2v

So total time in air will be

$t''=2\frac{2v}{g}$

$t''=4\frac{v}{g}$

t''=2t

5 0

4 years ago

At t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is 6.00 i + 4.00 j m/s2 . It moves at constan

Jet001 [13]

The particle moves with constant speed in a circular path, so its acceleration vector always points toward the circle's center.

At time $t_1$ , the acceleration vector has direction $\theta_1$ such that

$\tan\theta_1=\dfrac{4.00}{6.00}\implies\theta_1=33.7^\circ$

which indicates the particle is situated at a point on the lower left half of the circle, while at time $t_2$ the acceleration has direction $\theta_2$ such that

$\tan\theta_2=\dfrac{-6.00}{4.00}\implies\theta_2=-56.3^\circ$

which indicates the particle lies on the upper left half of the circle.

Notice that $\theta_1-\theta_2=90^\circ$ . That is, the measure of the major arc between the particle's positions at $t_1$ and $t_2$ is 270 degrees, which means that $t_2-t_1$ is the time it takes for the particle to traverse 3/4 of the circular path, or 3/4 its period.

Recall that

$\|\vec a_{\rm rad}\|=\dfrac{4\pi^2R}{T^2}$

where $R$ is the radius of the circle and $T$ is the period. We have

$t_2-t_1=(5.00-2.00)\,\mathrm s=3.00\,\mathrm s\implies T=\dfrac{3.00\,\rm s}{\frac34}=4.00\,\mathrm s$

and the magnitude of the particle's acceleration toward the center of the circle is

$\|\vec a_{\rm rad}\|=\sqrt{\left(6.00\dfrac{\rm m}{\mathrm s^2}\right)^2+\left(4.00\dfrac{\rm m}{\mathrm s^2}\right)^2}=7.21\dfrac{\rm m}{\mathrm s^2}$

So we find that the path has a radius $R$ of

$7.21\dfrac{\rm m}{\mathrm s^2}=\dfrac{4\pi^2R}{(4.00\,\mathrm s)^2}\implies\boxed{R=2.92\,\mathrm m}$

8 0

3 years ago

A 60-kg skate boarder is standing on his stationary board. A bigger, out of control 75-kg skate boarder crashes into him with a

andrezito [222]

Answer:

2.22m/s

Explanation:

Given parameters:

M1 = 60kg

M2 = 75kg

V1 = 0m/s

V2 = 4m/s

Unknown;

Velocity after collision = ?

Solution:

To solve this problem, we must understand that the momentum before and after collision of the bodies must be the same;

M1 V1 + M2 V2 = v(M1 + M2)

So;

60 x 0 + 75 x 4 = v (60 +75)

300 = 135v

v = 2.22m/s

3 0

3 years ago

Weight is measured in: grams, kilograms, metric tons, or pounds

sergejj [24]

'Gram', 'kilogram', and 'metric ton' are units of mass, not weight.

'Pound' can be either a unit of mass or of force. Most people
use it most of the time to mean weight.

8 0

3 years ago