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slavikrds [6]
3 years ago
12

How long will the energy in a 1470-kJ (350-kcal) cup of yogurt last in a woman doing work at the rate of 150 W with an efficienc

y of 20.0% (such as in leisurely climbing stairs)? Does this time imply that it is easy to consume more food energy than you can reasonably expect to work off with exercise?
Physics
1 answer:
Lyrx [107]3 years ago
5 0

Answer:

The 1470 kJ of energy supplied by the yogurt would be consumed by 150 W of work (efficiency of 20%) in about 32.7 h. Then if people is not careful, easily would have more energy from the food that the amount that can consume exercising.

Explanation:

Step 1.

  • Energy supplied: 1470 kJ = 1470000 J.
  • Rate of energy used for the : 150 W = 150 J/s. <em>This means that each second of this kind of work requieres 150 J of energy,</em>

Step 2

For this case, efficiency is defined as the relationship between the actual rate of energy used, to the rate of energy consumed to obtain it. So:

Eficiency=\frac{E_{obtain} }{E_{consumed} } \\

Then the rate of energy required for this work, is calculated solving for E_{Consumed}:

E_{consumed} =\frac{E_{obtain}}{Efficiency} =\frac{150\frac{J}{s} }{0.20} =750\frac{J}{s}

<em>This means that for a work that as a rate of 150 J/s , It requieres to consume energy at a rate of 750 J/s.</em>

Step 3

Now, it is possible to calculate how much time would be needed to consume the 1470000 J of energy of the yogurt. It done using this relationship:

Time=\frac{Energy}{rate}

Where Energy stands for the total amount of energy that would be consumed, and rate stans for the rate of energy consumption, Then the time would be:

Time=\frac{1470000J}{750\frac{J}{s} }=1960s=32.7 h

Then if for the consumption of 1470 kJ of energy is required almost 33 hours, Then is easy to see that the amount of enegy that can be obtain of food would much more than the amount that can be depleted by exercise

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Answer:

Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous. The process of a solid becoming a liquid is called melting.

4 0
3 years ago
A box is pulled with a horizontal force of 500N and moves 5m what is work done
dalvyx [7]
The answer to the question is shown below:

We all know that formula for solving work done is the force multiplied by distance covered:
Work done = Force x distance
Distance = 5m
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4 0
3 years ago
A police officer is parked by the side of the road, when a speeding car travelling at 50 mi/hrpasses. The police car immediately
Blababa [14]

Answer:

a) time taken to catch up with speeding car is 12.25 secs

b) the police car will travel 273.8 m to catch up with the speeding car

Explanation:

Given that;

speed of car V_{c} = 50 mi/hr = 22.352 m/s

acceleration of police car = 10 mi/hr = 4.47 m/s²

V_{f}  = 70 mi/hr = 31.29 m/s

Now time taken to reach maximum speed is t₁

so

V_{f} =  V_{i} + at₁

we substitute

31.29 = 0 + 4.47t₁

t₁ = 31.29 / 4.47

t₁  = 7 sec

now

d₁ = 0 + 1/2 × at₁²

d₁ = 0 + 1/2 × 0 + 4.47×(7)²

d₁ = 109.5 m

so distance travelled by the speeding car in time t₁  will be

d_{c} = V_{c} × t₁

we substitute

d_{c} = 22.352 × 7

d_{c}  = 156.46 m

now distance between polive car and speeding car

Δd =  d_{c} - d₁

Δd = 156.46 - 109.5

Δd = 46.96 m

time taken to cover Δd will be

t₂ = Δd / ( V_{f} - V_{c} )

t₂ = 46.96 / ( 31.29 - 22.352 )

t₂ = 46.96 / 8.938

t₂ = 5.25 sec

distance travelled by the police in time t₂ will be

d₂ = V_{f} × t₂

d₂ = 31.29 × 5.25

d₂ = 164.3 m

a) How long will it take before the officer catches up to the speeding car;

time taken to catch up with speeding car;

t = t₁ + t₂

t = 7 + 5.25

t = 12.25 secs

Therefore, time taken to catch up with speeding car is 12.25 secs

b)  how far will it have travelled in order to do so;

distance = d₁ + d₂

distance = 109.5 + 164.3

distance = 273.8 m

Therefore, the police car will travel 273.8 m to catch up with the speeding car

6 0
3 years ago
150c passes through cell in 30 seconds. cell has a potential difference of 12v. what is current in the circuit
zzz [600]

The current in the circuit is 5 A

Explanation:

The intensity of current is given by the equation:

I=\frac{q}{t}

where

I is the current

q is the amount of charge passing through a given point of the circuit in a time interval of t

For the cell in this problem, we have

q = 150 C is the charge

t = 30 s is the time interval

Substituting into the equation, we f ind

I=\frac{150}{30}=5 A

Learn more about current:

brainly.com/question/4438943

brainly.com/question/10597501

brainly.com/question/12246020

#LearnwithBrainly

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Answer:

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Muscular system:

muscles

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4 0
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