Why are fuel cells used on space shuttles instead of batteries?

Answer:

Explanation:

Mechanical advantage (M.A)of a machine is the ratio of load to effort

M.A= 5.5

load= 480N

effort= ?

Applying the formula and substituting to find the effort we have

[tex]M.A= \frac{load}{effort}[/tex]

[tex]5.5= \frac{480}{effort}\\\effort= \frac{480}{5.5} \\\effort= 87.27N[/tex]

Answer:

do you mind telling me what is it your asking so i can help ?

Explanation:

Answer:

Women are now allowed to participate in the Olympics. The original Olympic Games were open only to men.

Modern Olympic Games include many more events. The first Olympics included only a running event. Today, there are more than 20 different sports and almost 300 events.

The Olympics are held every two years, alternating between summer and winter. The ancient Olympics were originally held every four years in Olympia.

Athletes from countries around the world participate in the modern Olympics. The ancient Olympics consisted of athletes only from ancient Greece.

Explanation:

plato

Answer:

-0.08m/s²

Explanation:

Answer:

Explanation:

Given data

charge Q=4.0 * 10^-10 C

voltage v=250.0 V

applying the formula we can solve for C

[tex]Q=CV[/tex]

[tex]4.0 * 10^-10= C*250\\\C= \frac{4.0 * 10^-10}{250} \\\C= 1.6*10^-^1^2F[/tex]

Answer:

1.  Current in the circuit; 1.2 Amps

See attached image for the circuit.

2.  Equivalent resistor = 3 Ω

I = 0.3 amps

Potential difference across the battery terminals is: 0.9 V

Explanation:

Part 1.

The internal resistance of 2 ohms is simply added to the circuit in series as shown in the attached image.

Since now we have two resistances in series (2 ohms and 3 ohms) the total of this series combination is 5 ohms. Using Ohm's law, we can derive the current running through the circuit:

[tex]V=I\,\,R\\6\,V=I\,(5\,\Omega)\\I=\frac{6}{5} \,amps\\I=1.2\,\,amps[/tex]

Part 2.

Now we have a 1.5 V battery with a 2 ohm internal resistance, connected to two identical 6 ohm resistors.

a. The equivalent resistance presented by the two resistors in parallel:

[tex]\frac{i}{R_e} =\frac{1}{6\,\Omega} + \frac{1}{6\,\Omega} =\frac{1}{3\,\Omega} \\R_e=3\,\Omega[/tex]

b. Now the circuit can be represented by a 2 ohm resistor (internal battery resistance) plus a 3 ohm parallel equivalent resistor in series. That is a 5 ohm total resistance. Then Ohm's law becomes:

[tex]V=I\,\,R\\1.5\,V=I\,(5\,\Omega)\\I=\frac{1.5}{5} \,amps\\I=0.3\,\,amps[/tex]

c. The potential difference across the battery terminals must be the battery's EMF minus the potential drop in its internal resistance:

[tex]1.5\,V - (0.3\,\,amps)\,(2\,\Omega)=(1.5-0.6)\,V=0.9\,V[/tex]

Answer:

C

Explanation:

Answer:

C)  The gravity on the Moon is less than the gravity on Earth.

Explanation:

Since Moon is smaller than Earth, any mass on Moon will experience less gravitational force and so that mass will weigh less on Moon.

Answer:

the two vehicles will be moving at a speed of 6.16  m/s

Explanation:

This is a case of completely inelastic collision, therefore, the conservation of momentum can be written as:

[tex]m_1\,v_1+m_2\,v_2=(m_1+m_2)\,v_f[/tex]

which given the information provided results into:

[tex]m_1\,v_1+m_2\,v_2=(m_1+m_2)\,v_f\\(1250)\,(0)+(3550)\,(8.33)=(1250+3550)\,v_f\\29571.5=4800\,v_f\\v_f=6.16\,\,m/s[/tex]

Answer:

4 mph

Explanation:

This is because, if you divide the miles jogged by the hours you get 4.

Answer:

4 mph

Explanation:

Use the formula for average speed: [tex]Speed = \frac{Distance}{Time}[/tex]

The distance that Vanessa traveled is 8 miles and the time she traveled was 2 hours. Therefore, put those numbers in their corresponding spots in the formula and solve for Speed by dividing 8 and 2: [tex]Speed = \frac{8}{2}[/tex]

Answer:

Water is most dense.

Explanation:

Water is made up of hydrogen and oxygen atoms. Oxygen is smaller than carbon and its quite heavier, and the volume of water molecules is greater than the volume of oil molecules. It makes the water thicker than gasoline. Water molecules are therefore very attracted to one another and stack quite close around each other. This is another reason why water is denser than oil. in the same way, the water has more mass than an equal volume of alcohol and therefore it must be denser.

Answer:

K.E.=2.5Nm

Explanation:

m=20kg

v=0.5m/s

K.E.=?

K.E.=1/2mv²

K.E.=1/2×20kg×(0.5m/s)²

K.E.=10kg×0.25m²/s²

K.E.=2.5Nm

i hope this will help you :)

Answer:

v = 4.03 m/s

Explanation:

It is given that,

Distance covered by a lizard, d = 2.1 m

Time taken by lizard, t = 0.52 s

We need to find the average speed of the lizard. The distance covered divided by time taken is called the average speed of lizard. So,

[tex]v=\dfrac{d}{t}\\\\v=\dfrac{2.1\ m}{0.52\ s}\\\\v=4.03\ m/s[/tex]

So, the average speed of the lizard is 4.03 m/s.

Answer: 4.02 not 4.03

Explanation: I did on khan academy

Answer:

340 kg/m³

Explanation:

[tex]Relative density \: = \frac{density \: ofsubstance}{density \: of \: equal \: volume \: ofwater} [/tex]

density of water = 1000 kg/m³

density of the liquid = 0.34 × 1000

= 340 kg/m³

Answer:

Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

[tex]density \: = \: \frac{mass}{volume} [/tex]

density = 785/15 = 52.3 g/cm³

Note: you can as well leave your answer in kg/m³

Answer:

Sound travels quite fast and sound wave must pass through a medium, such as air.

To measure a sound in classroom you will require to measure the time it takes a sound to travel a measured distance using stopwatch and meter stick but it would be difficult because walls of classroom will create echos echos.

Echos are reflections of sounds which causes timing errors and make difficult to meausre the speed of sound.

Answer:

gamma rays, ultraviolet, infrared, radio

Explanation:

Because on the Electromagnetic spectrum wavelength increases from the gamma end to radio end and frequency decrease in that order

Answer:

radio → infrared → ultraviolet → gamma

Explanation: yeaaahhh its c

Answer:

The correct option is;

(A) 25.8 cmHg

Explanation:

The given parameters are;

The height of the mountain over which the eagle is flying = 2700 m

The average density of air, ρₐ = 1.3 kg/m³

The atmospheric pressure at sea level = 76 cmHg = 0.76 mHg

The density of mercury, [tex]\rho _m[/tex] = 13,600 kg/m³

The formula for pressure, p, is p = ρ·g·h

The pressure in the atmosphere = 13,600 × 0.76 × g = 10,336·g

The equivalent height of air is found as follows;

1.3 × g × h = 10,336·g

h = 10,336/1.3 = 7,950.769 meters

Therefore;

The pressure of the atmosphere at 2,700 meters, p₂₇₀₀ = (2,700/7,950.769) × 76 cm Hg

Which gives;

p₂₇₀₀ = 25.808 cmHg ≈ 25.8 cmHg.

Answer:

The answer is

Hope this helps you

Answer:

B. heavier elements

Explanation:

The Available options are:

A. Award an indirect free kick to Team B for incidental contact.

B.  Award a direct free kick to Team B.

C.  Allow play to continue as the handling was incidental but issue a caution to the player at the next stoppage of play.  

D.  Allow play to continue.

Answer:

Allow play to continue.

Explanation:

IFAB (International Football Association Board) has approved various means to clarify the issue of handball in foodtball.

Hence, some of the cases include:

1. Should the the ball touches a player's hand/arm immediately from their own head/body/foot or the head/body/foot of another player.

2. the ball touches a player's hand/arm close to their body and has not made their silhouette unnaturally bigger.

3. a player is falling and the ball touches their hand/arm when it is between their body and the ground (but not extended to make the body bigger).

4. Additionally, should the goalkeeper attempt to clear a ball from a teammate but fails, the goalkeeper is allowed to handle the ball.

Hemce, Since a14 who did not see the ball coming and the ball strikes her in the back of the hand as her hand is at her side. the proper call would be to: ALLOW PLAY CONTINUE

EXAMPLE

BIKE/STROLLER - WHEEL AND AXLE

SCISSORS/HEDGE CUTTER - LEVER

STAIRS - INCLINED PLANED

SCREW DRIVER/SCREW/NAILS- SCREW

AXE - WEDGE

WELL - PULLEY

Its not much but hope this help you

in a parallel circuit equivalent resistor is,

1/R = 1/20 + 1/100 + 1/50

so 1/R = 5/100 + 1/100 + 2/100

= 8 /100

1/R = 8/100

8R = 100

R = 12.5 ohms

b) v = IR

125 = I × 12.5

I = 125/12.5

I = 10A

c) resistor with 20 ohms

v = ir

125 = 20I

I = 6.25 A

the resistor with 100

125 = 100I

I = 125/100

= 1.25A

the resistor with 50 ohms

125 = 50I

I = 125 /50

2.5A

if u want to make sure all these calculations are crct add them up and see

A resistor is an electrical component that provides electrical resistance or limits the flow of current in a circuit. For calculating resistance (R) values of voltage(V) and current (I) should be known.

The correct quantities are (a) 12.5 ohms, (b) 10A (c)  6.25 A, 1.25A, 2.5A (d) 125 V  (e) 781.25 W, 156.25 W and 312.5 W.

The calculations are as follows:

Given,

(a) Equivalent resistance in parallel resistor:

[tex]\rm \dfrac{1}{Req} = \dfrac{1} {R1} + \dfrac{1} {R2} + \dfrac{1} {R3}[/tex]

[tex]\rm \dfrac{1}{Req} = \dfrac{1} {20} + \dfrac{1} {100} + \dfrac{1} {50}[/tex]

So,

[tex]\rm \dfrac{1}{Req} = \dfrac{5} {100} + \dfrac{1} {100} + \dfrac{2} {100}[/tex]

[tex]\rm \dfrac{1}{Req} = \dfrac{8} {100}[/tex]

Req = 12.5 ohms

(b) Current can be calculated using the formula:

V = IR

Where,

V = 125 V

I = ?

R = 12.5 ohms

Substituting values in equation:

[tex]\rm 125 = I \times 12.5[/tex]

[tex]\rm I = \dfrac {125 }{12.5} \\\\I = 10 A[/tex]

Therefore, current is 10 Amperes.

(c) Current through each resistor:

Given,

V = 125 V

I = ?

[tex]\rm 125 = I \times 20\\\\I1 = 6.25 A[/tex]

[tex]\rm 125 = I \times 100\\\\I2= 1.25A[/tex]

[tex]\rm 125 = I \times 50 \\\\I3= 2.5 A[/tex]

(d) Voltage drop across each resistor in a parallel circuit can be calculated by:

For parallel:

Given from (c)

I1 = 6.25

I2= 1.25 A

I3 = 2.5 A

[tex]\rm V1 = 6.25 \times 20\\V 1 = 125[/tex]

[tex]\rm V2 = 1.25 \times 100\\ V2= 125[/tex]

[tex]\rm V3 = 2.5 \times 50\\ V3= 125[/tex]

(e) Power dissipated by each source can be calculated by the following formula:

Given,

V = 125 V

[tex]\rm P = \dfrac {V^{2}}{ R}[/tex]

Resistor 1:

[tex]\rm P = \dfrac {(125)^ 2 }{ 20}\\\\P1 = 781.25 W[/tex]

Resistor 2:

[tex]\rm P = \dfrac {(125)^ 2 }{ 100}\\\\P2 = 156.25 W[/tex]

Resistor 3:

[tex]\rm P = \dfrac {(125)^ 2 }{ 50}\\\\P3 = 312.5 W[/tex]

Therefore, (a) 12.5 ohms, (b) 10A (c)  6.25 A, 1.25A, 2.5A (d) 125 V (e) 781.25 W, 156.25 W and 312.5 W.

To learn more about resistors in parallel circuit follow the link:

https://brainly.com/question/25686930

Answer:

because lwhen they are made longer than the turning effect of force is more and its easy to work it out.

Answer:

1 mm

Explanation:

E = ½ kx²

0.025 J = ½ (50,000 N/m) x²

x = 0.001 m

x = 1 mm

Answer:

gas is non-renewable resource

Explanation:

Answer:

Gas

Explanation:

There are two types of energy sources, renewable and non-renewable.

Solar energy, wind energy, and hydroelectric are an example of renewable energy.

Fossil fuels like gas, coal, and petroleum are an example of non-renewable energy.

Answer:

Output work is always less than input work due to effect of friction. Machines are frictionless in practice, the efficiency of a machine can never be 100%.

Hope this helps..

Good luck on your assignment..

Answer:

Friction

Explanation:

This question is incomplete because part of the content is missing; here is the complete question:

Ingrid wrote the hypothesis below.  If the temperature of a liquid increases, the density of the liquid decreases because the particles move farther apart.

What are the variables in her hypothesis?

A. The independent variable is the temperature, and the dependent variable is the density.

B. The independent variable is the density, and the dependent variable is the temperature.

C. The independent variable is the temperature, and the dependent variable is the distance between particles.

D. The independent variable is the distance between particles, and the dependent variable is the temperature.

The answer to this question is A. The independent variable is the temperature, and the dependent variable is the density.

Explanation:

To begin, the variables in an experiment are the factors being studied or analyzed, which are expressed in the hypothesis. According to this, the two variables in the experiment are the temperature and the density.

Additionally, in experiments, it is common one of the variables is independent, which is the factor manipulated by the researcher, and the other is dependent as this is expected to be changed by the first variable. If this is applied to the experiment described, the temperature is independent because this will be manipulated by Ingrid to prove density changes. Also, the density is expected to be affected by the first variable, and therefore density is the dependent variable.

Answer:

160 m

Explanation:

For computing the distance first we have to determine the acceleration which is shown below:

v = u + at

where,

v = 0 = initial velocity

u = 40 = uniformly to a speed

t = 8 = time

So, the a is

= 40 ÷ 8

= 5 m/s

Now we have to use the distance formula i.e

d = ut + 1 ÷ 2 at^2

= 1 ÷2 × 5 × 8^2

= 160 m

Basically we have to applied the above formulas so that the distance could come

Answer:

D. not enough information to decide

Explanation:

i dont understand >.<