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3 years ago

Why are more firefighters needed to help hold the fire hose when the increase of water flow increases the force of the water?

Physics

2 answers:

kondaur [170]3 years ago

6 0

they are needed to withstand the recoil as tons of water are ejectedd at high speed ... like a cannon

polet [3.4K]3 years ago

3 0

Answer:

A. When the force of the water increases, the reaction force pushing the hose back also increases.

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A particular engine has a power output of 8 kW and an efficiency of 37%. If the engine expels 10994 J of thermal energy in each

VARVARA [1.3K]

Answer:

(a) 17450.8 J (B) 1.239 sec

Explanation:

We have given power output =8 KW

Heat expelled = 10994 j

Efficiency =37% = 0.37

(A) We know that efficiency $\eta =1-\frac{heat\ expelled}{heat\ input}$

$0.37=1-\frac{10994}{heat\ input}$

Heat input =17450.8 J

(B) Work done by the engine is = 17450.8-10994=6456.8 j

Power output is given by 8 KW =8000 W

So time for each cycle is $\frac{8000}{6456.8}=1.239 sec$

3 0

3 years ago

As a baseball is being caught, its speed goes from 43 to 0 m/s in about 0.003 s. Its mass is 0.145 kg. (Take the direction the b

juin [17]

The question is incomplete, these are the missing parts of the question.

b) What is the baseball's acceleration in g's? (Indicate the direction with the sign of your answer.)

(b) What is the size of the force acting on it?

Answer:

a) -14333.3ms-2

b) -1462.58g

c) 2078N

Explanation:

The acceleration (deceleration) is easily found from from the information provided. Then the acceleration is obtained in terms of g as shown in the solution attached. The force is obtained from F=ma as shown in the image attached. Note the acceleration is negative because the ball was coming to rest. (The ball was caught).

6 0

3 years ago

A car has a mass of 1,000 kilograms. The weight of the car is blank newtons. Use g = 9.8 N/kg for gravity.

Komok [63]

The weight of an object is mass*acceleration. In this case mass*g.
1000*9.8=9800
So the car has a weight of 9800 N.

3 0

3 years ago

Sodium hydroxide is a common for

postnew [5]

Sodium hydroxide is used to manufacture many everyday products, such as paper, aluminum, commercial drain and oven cleaners, and soap and detergents.

plz mark me as brainliest :)

8 0

3 years ago

An automobile battery has an emf of 12.6 V and an internal resistance of 0.0600 . The headlights together present equivalent res

murzikaleks [220]

Answer:

(a) $V=11.86\ V$

(b) $V=9.76\ V$

Explanation:

<u>Electric Circuits</u>

Suppose we have a resistive-only electric circuit. The relation between the current I and the voltage V in a resistance R is given by the Ohm's law:

$V=R.I$

(a) The electromagnetic force of the battery is $\varepsilon =12.6\ V$ and its internal resistance is $R_i=0.06\ \Omega$ . Knowing the equivalent resistance of the headlights is $R_e=5.2\ \Omega$ , we can compute the current of the circuit by using the Kirchhoffs Voltage Law or KVL:

$\varepsilon=i.R_i+i.R_e=i.(R_i+R_e)$

Solving for i

$\displaystyle i=\frac{\varepsilon}{ R_i+R_e}=\frac{12}{0.06+5.2}=2.28\ A$

i=2.28\ A

The potential difference across the headlight bulbs is

$V=\varepsilon -i.R_i=12\ V-2.28\ A\cdot 0.06\ \Omega=11.86\ V$

$V=11.86\ V$

(b) If the starter motor is operated, taking an additional 35 Amp from the battery, then the total load current is 2.28 A + 35 A = 37.28 A. Thus the output voltage of the battery, that is the voltage that the bulbs have is

$V=\varepsilon -i.R_i=12\ V-37.28\ A\cdot 0.06\ \Omega=9.76\ V$

5 0

3 years ago