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lisabon 2012 [21]

3 years ago

10

What do wind and moving water have in common? Select one: They both have electrical energy They both have elastic potential ener

gy They both have electromagnetic energy (light) They both have kinetic energy

1 answer:

ozzi3 years ago

7 0

They both have kinetic energy because they are both moving and have force.
Hope this helped! :)

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4. What are 3 things that you can think of doing, that would reduce<br> your electricity bill?

Cloud [144]

Turn off standby appliances.
Install a smart thermostat.
Turn down your thermostat.
Buy efficient appliances.
Install a new boiler.
Wash clothes at a lower temperature.
Be smarter about water.
Invest in double glazing.

3 0

3 years ago

A kangaroo jumps straight up to a vertical height of 1.66 m. How long was it in the air before returning to Earth? Express your

Nataly [62]

Answer:

The kangaroo was 1.164s in the air before returning to Earth

Explanation:

For this we are going to use the equation of distance for an uniformly accelerated movement, that is:

$x = x_{0} + V_{0}t + \frac{1}{2}at^2$

Where:

x = Final distance

xo = Initial point

Vo = Initial velocity

a = Acceleration

t = time

We have the following values:

x = 1.66m

xo = 0m (the kangaroo starts from the floor)

Vo = 0 m/s (each jump starts from the floor and from a resting position)

a = 9.8 m/s^2 (the acceleration is the one generated by the gravity of earth)

t =This is just the time it takes to the kangaoo reach the 1.66m, we don't know the value.

Now replace the values in the equation

$x = x_{0} + V_{0}t + \frac{1}{2}at^2$

$1.66 = 0 + 0t + \frac{1}{2}9.8t^2$

$1.66 = 4.9t^2$

$\frac{1.66}{4.9} = t^2$

$\sqrt{0.339} = t\\ t = 0.582s$

It takes to the kangaroo 0.582s to go up and the same time to go down then the total time it is in the air before returning to earth is

t = 0.582s + 0.582s

t = 1.164s

The kangaroo was 1.164s in the air before returning to Earth

5 0

4 years ago

758 j of heat are added to 0.750 kg of copper. how much does its temperature change?(unit=degrees c) PLEASE HELPPPPPPP MEEEEEE

DiKsa [7]

Answer:

$2.6^{\circ}C$

Explanation:

When a substance is supplied with a certain amount of heat energy, the temperature of the substance increases according to the equation

$Q=mC\Delta T$

where

m is the mass of the substance

Q is the amount of energy supplied

C is the specific heat of the substance

$\Delta T$ is the temperature change

In this problem:

Q = 758 J is the energy supplied

m = 0.750 kg is the mass of the sample

$C=385 J/kg^{\circ}C$ is the specific heat of copper

Re-arranging the equation, we can find the increase in temperature:

$\Delta T=\frac{Q}{mC}=\frac{758}{(0.750)(385)}=2.6^{\circ}C$

5 0

4 years ago

A heat pump used to heat a house runs about one-third of the time. The house is losing heat at an average rate of 22,000 kJ/h. I

Natali5045456 [20]

The power that heat pump draws when running will be 6.55 kj/kg

A heat pump is a device that uses the refrigeration cycle to transfer thermal energy from the outside to heat a building (or a portion of a structure).

Given a heat pump used to heat a house runs about one-third of the time. The house is losing heat at an average rate of 22,000 kJ/h and if the COP of the heat pump is 2.8

We have to determine the power the heat pump draws when running.

To solve this question we have to assume that the heat pump is at steady state

Let,

Q₁ = 22000 kj/kg

COP = 2.8

Since heat pump used to heat a house runs about one-third of the time.

So,

Q₁ = 3(22000) = 66000 kj/kg

We known the formula for cop of heat pump which is as follow:

COP = Q₁/ω

2.8 = 66000 / ω

ω = 66000 / 2.8

ω = 6.66 kj/kg

Hence the power that heat pump draws when running will be 6.55 kj/kg

Learn more about heat pump here :

brainly.com/question/1042914

#SPJ4

5 0

2 years ago

Please help me with this problem for physics !

Westkost [7]

Answer:

2 m/s²

Explanation:

velocity =

$\frac{20 - 0}{10}$

20/10 = 2

4 0

3 years ago