All categories

3 years ago

All of the following are examples of ways to improve energy efficiency of heating systems, except _______.

Physics

1 answer:

Yuri [45]3 years ago

5 0

Answer:

D. Opening the front door in winter to filter and clean warm ai

Explanation:

All of the following are examples of ways to improve energy efficiency of heating systems, except _______.

A. Closing off rooms that aren’t in use.

B. Frequently cleaning the furnace filter.

C. Fixing cracks in the walls and floor.

D. Opening the front door in winter to filter and clean warm air

for an heating systems it is better to keep the front door shut so that all the heat energy does not escape outside.

when heat energy is within a closed system ,it can still be utilized to keep the inhabitants warm otherwise there will be an exchange with the cold from winter fall outside the air, and the heating system's efficiency will be reduced

You might be interested in

Why is heat acclimatization important?

kicyunya [14]

Answer:

Heat acclimatization :

It is the biological adaptations or we can say that it coverts according to the present environment.It also reduce the strain and maintain the normal temperature and heart rate.Heat acclimatization also increase the comfort and reduce all the mental strain and also protect out liver ,muscles ,kidneys and brain fro the injury.

5 0

3 years ago

A 45.0 kg ice skater needs a 25 N horizontal force to get moving on a smooth ice surface. What is the coefficient of friction be

SVEN [57.7K]

The horizontal force : f = k*N
k- coefficient of friction
k = f /N
N = m * g = 45 kg * 9.81 m/s² = 441.45 N
k = 25 N : 441.45 N = 0.057
Answer C) 0.057

7 0

2 years ago

You stand on a frictional platform that is rotating at 1.8 rev/s. Your arms are outstretched, and you hold a heavy weight in eac

dusya [7]

Answer:

20.62361 rad/s

489.81804 J

Explanation:

$I_i$ = Initial moment of inertia = 9.3 kgm²

$I_f$ = Final moment of inertia = 5.1 kgm²

$\omega_i$ = Initial angular speed = 1.8 rev/s

$\omega_f$ = Final angular speed

As the angular momentum of the system is conserved

$I_i\omega_i=I_f\omega_f\\\Rightarrow \omega_f=\dfrac{I_i\omega_i}{I_f}\\\Rightarrow \omega_f=\dfrac{9.3\times 1.8}{5.1}\\\Rightarrow \omega_f=3.28235\ rev/s=3.28235\times 2\pi=20.62361\ rad/s$

The resulting angular speed of the platform is 20.62361 rad/s

Change in kinetic energy is given by

$\Delta K=\dfrac{1}{2}(I_f\omega_f^2-I_i\omega_i^2)\\\Rightarrow \Delta K=\dfrac{1}{2}(5.1\times (20.62361)^2-9.3\times (1.8\times 2\pi)^2)\\\Rightarrow \Delta K=489.81804\ J$

The change in kinetic energy of the system is 489.81804 J

As the work was done to move the weight in there was an increase in kinetic energy

6 0

3 years ago

Elliot jumps up and down on a pogo stick. He weighs 600.N, and his pogo stick has a spring with spring constant 1100N/m. What is

tia_tia [17]

From conservation of energy, the height he will reach when he has gravitational potential energy 250J is 0.42 meters approximately

The given weight of Elliot is 600 N

From conservation of energy, the total mechanical energy of Elliot must have been converted to elastic potential energy. Then, the elastic potential energy from the spring was later converted to maximum potential energy P.E of Elliot.

P.E = mgh

where mg = Weight = 600

To find the height Elliot will reach, substitute all necessary parameters into the equation above.

250 = 600h

Make h the subject of the formula

h = 250/600

h = 0.4167 meters

Therefore, the height he will reach when he has gravitational potential energy 250J is 0.42 meters approximately

Learn more about energy here: brainly.com/question/24116470

4 0

2 years ago

A 0.050 kg bullet strikes a 5.0 kg wooden block with a velocity of 909 m/s and embeds itself in the block which fies off its sta

serg [7]

Answer:

The final velocity of the bullet is 9 m/s.

Explanation:

We have,

Mass of a bullet is, m = 0.05 kg

Mass of wooden block is, M = 5 kg

Initial speed of bullet, v = 909 m/s

The bullet embeds itself in the block which flies off its stand. Let V is the final velocity of the bullet. The this case, momentum of the system remains conserved. So,

$mv=(m+M)V\\\\V=\dfrac{mv}{m+M}\\\\V=\dfrac{0.05\times 909}{0.050+5}\\\\V=9\ m/s$

So, the final velocity of the bullet is 9 m/s.

5 0

3 years ago