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4 years ago

Which of the following can be a variable? Select all that are correct (Hint: Three are

Physics

2 answers:

gladu [14]4 years ago

7 0

A and B and D are correct because variables has letters not numbers

Tresset [83]4 years ago

4 0

The only one that can’t be a variable is 3 because variables are letters you solve for to get numbers!

Hope I was helpful!

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The energy released from condensation in thunderstorms can be very large. Calculate the energy (in J) released into the atmosphe

makkiz [27]

Answer:

7.19 * 10^14J

Explanation:

Given that

Density of water Pwater= 1000kg/m3

R=2.1km = 2.1*10^3m

H= 2.3cm. = 2.3*10^-2m

Lv water= 2256 * 10^3J/kg

First, mass of water need to be calculated, using an imaginary cylinder

Density= Mass /Volume

Mass= Density* Volume

Volume of a cylinder= πR2h

Therefore mass= PπR2H

= 1000 * π * (2.1 *10^3)^2 * (2.3 * 10^-2)

= 3.18 *10^8

Heat Released Qv = mLV

= 3.18*10^8 * 2236*10^3

= 7.19 * 10^14J

7 0

4 years ago

Read 2 more answers

What is the equilibrium concentration of ibr?

asambeis [7]

IBR is the thermal decomposition of iodine(I) bromide to produce iodine and bromine. This reaction takes place at a temperature of over 40,5°C and is written as:

2IBr ⇄ I2 + Br2

Equilibrium is a state of dynamic balance where the ratio of the product and reactant concentrations is constant. You can calculate the equilibrium concentration if you know the equilibrium constant Kc (Kc=I^2*Br^2/IBR^2) and the initial concentration for the reaction. The initial concentration is obtained from ICE Table.

3 0

3 years ago

Suppose that a balloon is being filled with air at a rate of 10 cm3/s. (Assume that theballoon is a perfect sphere.) At what rat

Basile [38]

Answer:

Therefore the surface area of the balloon is increased at 4 cm³/s.

Explanation:

The balloon is being filled with air at a rate of 10 cm³/s

It means the volume of the balloon is increased at a rate 10 cm³/s.

i.e $\frac{dv}{dt} =10 cm^3/s$

Consider r be the radius of the balloon.

The volume of of a sphere is

$v=\frac{4}{3} \pi r^3$

Differentiate with respect to t

$\frac{dv}{dt} =\frac{4}{3} \pi \times 3r^2\frac{dr}{dt}$

$\Rightarrow 10 =4\pi r^2\frac{dr}{dt}$

$\Rightarrow \frac{dr}{dt}=\frac{10}{4\pi r^2}$

The surface of area of the balloon is(S) = $4\pi r^2$

$S=4\pi r^2$

Differentiate with respect to t

$\frac{dS}{dt} =4\pi\times2r\frac{dr}{dt}$

$\Rightarrow \frac{dS}{dt} =8\pi r\frac{dr}{dt}$

Putting the value of $\frac{dr}{dt}$

$\Rightarrow \frac{dS}{dt} =8\pi r\times\frac{10}{4\pi r^2}$

$\Rightarrow \frac{dS}{dt} =\frac{20}{ r}$

Given that r = 5 cm

$[\frac{dS}{dt}]_{r=5} =\frac{20}{ 5}$ =4 cm³/s

Therefore the surface area of the balloon is increased at 4 cm³/s.

5 0

4 years ago

Which of the following is a possible use for nuclear energy?

belka [17]

Nuclear energy can be used to power all of the above choices. Nuclear power plants produce radioactive waste that must be stored properly. It is very impossible for a nuclear power plant to have no waste at all since lots of chemicals are used to create the process as it gives energy to other machines, weapons such as bombs and powering submarines. Radioactive waste can not be released into local water supplies since the wastes are very radioactive and may cause mutation to the fishes and bioaccumulation which will affect humans as well. It will also cause air pollution if the chemicals are not stored properly.

5 0

4 years ago

Read 2 more answers

You are investigating an elevator accident which happened in a tall building. An elevator in this building is attached to a stro

Advocard [28]

Answer:

a) F = 2250 Ib

b) F = 550 Ib

c) new max force ( F newmax ) = 2850 Ib

Explanation:

A) The force the wall of the elevator shaft exert on the motor if the elevator starts from rest and goes up

max capacity of elevator = 24000 Ibs

counterweight = 1000 Ibs

To calculate the force (F) :

we first calculate the Tension using this relationship

Counterweight (1000) - T = ( 1000 / g ) ( g/4 )

Hence T = 750 Ib

next determine F

750 + F - 2400 = 2400 / 4

hence F = 2250 Ib

B ) calculate Tension first

T - 1000 = ( 1000/g ) ( g/4)

T = 1250 Ib

F = 2400 -1250 - 2400/ 4

F = 550 Ib

C ) determine design limit

Max = 2400 * 1.2 = 2880 Ib

750 + new force - 2880 = 2880 / 4

new max force ( F newmax ) = 2850 Ib

8 0

4 years ago