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Iteru [2.4K]
2 years ago
8

A ten year old boy (26 kg) sits on a wheeled office chair (16kg) holding a fire extinguisher (18kg when empty). He points the di

scharge horn to the right and ejects 9kg of carbon dioxide at 20m/s. What is his velocity after the fire extinguisher is emptied
Physics
1 answer:
madreJ [45]2 years ago
3 0

Answer:

30m/s

Explanation:

Suppose there's no friction between the office chair and the floor. The only thing that impact the motion of the boy is the ejected carbon dioxide. We can apply the law of momentum conservation to find the his (the boy, the chair and the empty extinguisher) after the extinguisher is emptied.

Before the ejects, the system momentum is 0, due to at rest and no speed

After the ejects, momentum of the carbon dioxide is

9*20 = 180 kg m/s

The momentum of his is then

P + 180 = 0

P = -180

MV = -180

(26 + 16 + 18)V = - 180

V = -180/(26 + 16 + 18) = -30 m/s

So he would have a speed of 30m/s in the opposite of the ejected carbon dioxide direction

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A box of mass 8 kg slides across a frictionless surface at an initial speed 1.5 m/s into a relaxed spring of spring constant 69
Sav [38]

Answer:

1.1 sec

Explanation:

m = mass of the box = 8 kg

k = spring constant of the spring = 69 N/m

v = initial speed of the box = 1.5 m/s

t = time period of oscillation of box in contact with the spring

Time period is given as

t = \pi \sqrt{\frac{m}{k}}

Inserting the values

t = (3.14) \sqrt{\frac{8}{69}}

t = 1.1 sec

5 0
2 years ago
A 6.0-cm-diameter, 11-cm-long cylinder contains 100 mg of oxygen (O2) at a pressure less than 1 atm. The cap on one end of the c
butalik [34]

Answer:

The temperature of the gas is 1197.02 K

Explanation:

From ideal gas law;

PV = nRT

Where;

P is the pressure of the gas

V is the volume of the gas

R is ideal gas constant = 8.314 L.kPa/mol.K

T is the temperature of the gas

n is the number of moles of gas

Volume of the gas in the cylindrical container = πr²h

Given;

r = 6/2 = 3 cm = 0.03 m

h = 11 cm = 0.11 m

V = π × (0.03)² × 0.11 = 3.11 × 10⁻⁴ m³ = 0.311 L

number of moles of oxygen gas = Reacting mass / molar mass

=\frac{0.1}{32} = 0.003125, moles

T = \frac{PV}{nR} = \frac{100X0.311}{0.003125X8.314} =1197.02K

Therefore, the temperature of the gas is 1197.02 K

6 0
2 years ago
A jet engine gets its thrust by taking in air, heating and compressing it, and
nadya68 [22]

Answer:

F=ma=20\ Kg\ 400\ m/s^2=8,000\ Nw

Explanation:

Thrust is known as a reaction force which appears when a system expels or accelerates mass in one specific direction. If we know the acceleration and the mass of the air expelled by the jet engine, we can compute the thrust .

The acceleration is calculated by using the dynamics formula

\displaystyle a=\frac{v_f-v_o}{t}

The values are  

v_f=500\ m/s,\ v_o=100\ m/s,\ t=1\ sec

\displaystyle a=\frac{500-100}{1}=400\ m/s^2

The thrust is

F=ma=20\ Kg\ 400\ m/s^2=8,000\ Nw

4 0
2 years ago
An activity that is relatively short in time (< 10 seconds) and has few repetitions predominately uses the _____________ ener
tensa zangetsu [6.8K]
An activity that is relatively short in time <10 seconds and has few repetitions predominantly uses the ATP/PC energy system. The cellular respiration procedure that changes food energy into ATP which is a form of energy is largely reliant on oxygen obtainability. During exercise the source and request of oxygen obtainable to muscle is unnatural by period and strength and by the individual’s cardiorespiratory suitability level. 
Steps of the ATP-PC system:


1. Primarily, ATP kept in the myosin cross-bridges which is microscopic contractile parts of muscle is broken down to issue energy for muscle shrinkage.  This action consents the by-products of ATP breakdown which are the adenosine diphosphate and one single phosphate all on its own.


2. Phosphocreatine is then broken down by the enzyme creatine kinase into creatine and phosphate.


3. The energy free in the breakdown of PC permits ADP and Pi to rejoin creating more ATP.  This newly made ATP can now be broken down to issue energy to fuel activity. 
5 0
2 years ago
Floor lamps usually have a base with large inertia, while the long body and top have much less inertia. Part A If you want to sh
Novay_Z [31]

Answer:

When a an object is been rotated its resistance capacity to that rotational force is know as rotational inertia  and this mathematically given as

          I = mr^2

   Where m is the mass

                r is the rotation radius

For the spinning of the lamp as a baton to work the location of the center of mass of the floor lamp needs to be located

This is more likely to be located closer to base of the lamp as compared to the top, so success of spinning a floor lamp like a baton is highly likely if the lamp is grabbed closer to the base because that is where the position of its center of mass is likely to be.

Explanation:

5 0
2 years ago
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