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N76 [4]
1 year ago
14

A heater marked 2000W/3000W is switched on for 4 hours. For the first hour it is on the highest setting and for the last 3 hours

it is on the lowest setting
1.1 How much energy does it transfer to the room in kWh (9kWh)
​
Physics
1 answer:
Leni [432]1 year ago
3 0

Answer:

9 kW-hr

Explanation:

3000 W  = 3 kW          for 1 hr =    <u>3 kW - hr </u>

2000 W  = 2 kW          for 3 hr =  <u> 6 kW -hr</u>

<u />

total power =  <u> 3 + 6 = 9 kW-hr</u>

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A spring gun is made by compressing a spring in a tube and then latching the spring at
inn [45]

Answer:

a)v=13.2171\,m.s^{-1}

b)H=8.9605\,m

Explanation:

Given:

mass of bullet, m=4.97\times 10^{-3}\,kg

compression of the spring, \Delta x=0.0476\,m

force required for the given compression, F=9.12 \,N

(a)

We know

F=m.a

where:

a= acceleration

9.12=4.97\times 10^{-3}\times a

a\approx 1835\,m.s^{-2}\\

we have:

initial velocity,u=0\,m.s^{-1}

Using the eq. of motion:

v^2=u^2+2a.\Delta x

where:

v= final velocity after the separation of spring with the bullet.

v^2= 0^2+2\times 1835\times 0.0476

v=13.2171\,m.s^{-1}

(b)

Now, in vertical direction we take the above velocity as the initial velocity "u"

so,

u=13.2171\,m.s^{-1}

∵At maximum height the final velocity will be zero

v=0\,m.s^{-1}

Using the equation of motion:

v^2=u^2-2g.h

where:

h= height

g= acceleration due to gravity

0^2=13.2171^2-2\times 9.8\times h

h=8.9129\,m

is the height from the release position of the spring.

So, the height from the latched position be:

H=h+\Delta x

H=8.9129+0.0476

H=8.9605\,m

4 0
3 years ago
What is the pressure exerted by a column of fresh water 10m high<br>(p=1000kg/m3 and g=10m/s)​
alexira [117]
  • Height (h) = 10 m
  • Density (ρ) = 1000 Kg/m^3
  • Acceleration due to gravity (g) = 10 m/s^2
  • We know, pressure in a fluid = hρg
  • Therefore, the pressure exerted by a column of fresh water
  • = hρg
  • = (10 × 1000 × 10) Pa
  • = 100000 Pa

<u>Answer</u><u>:</u>

<u>1000</u><u>0</u><u>0</u><u> </u><u>Pa</u>

Hope you could understand.

If you have any query, feel free to ask.

8 0
3 years ago
What is the formula for force?
Vitek1552 [10]
Choice 'b' is one possible way to state
Newton's second law of motion.

The other choices are meaningless.
8 0
3 years ago
The tip of the second hand of a clock moves in a circle of 20 cm circumference. In one minute the hand makes a complete revoluti
Cerrena [4.2K]

Answer:

v_{avg} = 0

Explanation:

As we know that average velocity is defined as the ratio of total displacement of the object and its time interval.

so here we can say

v_{avg} = \frac{displacement}{time}

now we know that in one complete revolution the total displacement of the tip of the seconds hand is zero

because it will have same position after one complete revolution from where it starts

so here we can say that the average velocity will be zero

v_{avg} = 0

7 0
3 years ago
a spherical mirror is cut in half horizontally will an image be formed by the bottom half of the mirror how
monitta

Answer:

Explanation:

the spherical mirror can form an image even if it is cut in half horizontally , but the image formed may be blurred.

pls mark as brainliest if you find it helpful

7 0
3 years ago
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