What activity is mainly a strength training excerise?

You set your stationary bike on a high 80-N friction-like resistive force and cycle for 30 min at a speed of 8.0 m/s . Your body

stellarik [79]

A) The change in internal chemical energy is $1.15\cdot 10^7 J$

B) The time needed is 1 minute

Explanation:

First of all, we start by calculating the power output of you and the bike, given by:

$P=Fv$

where

F = 80 N is the force that must be applied in order to overcome friction and travel at constant speed

v = 8.0 m/s is the velocity

Substituting,

$P=(80)(8.0)=640 W$

The energy output is related to the power by the equation

$P=\frac{E}{t}$

where:

P = 640 W is the power output

E is the energy output

$t = 30 min \cdot 60 = 1800 s$ is the time elapsed

Solving for E,

$E=Pt=(640)(1800)=1.15\cdot 10^6 J$

Since the body is 10% efficient at converting chemical energy into mechanical work (which is the output energy), this means that the change in internal chemical energy is given by

$\Delta E = \frac{E}{0.10}=\frac{1.15\cdot 10^6}{0.10}=1.15\cdot 10^7 J$

B)

From the previous part, we found that in a time of

t = 30 min

the amount of internal chemical energy converted is

$E=1.15\cdot 10^7 J$

Here we want to find the time t' needed to convert an amount of chemical energy of

$E'=3.8\cdot 10^5 J$

So we can setup the following proportion:

$\frac{t}{E}=\frac{t'}{E'}$

And solving for t',

$t'=\frac{E't}{E}=\frac{(3.8\cdot 10^5)(30)}{1.15\cdot 10^7}=1 min$

Learn more about power and energy:

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3 0

3 years ago

NEWTON LAWS

Vika [28.1K]

Answer:

it's Newton's first law of motion

As the law states that.

Everybody continues in its rest or of uniform motion unless an external force acts on it.

8 0

3 years ago

Read 2 more answers

Bob and John are pulling in different directions. If Bob is pulling to the right with a force of 10N, and John is pulling to the

kykrilka [37]

Answer:

A) -2N

B) Left

C) -0.5

Explanation:

A) -12 + 10

B) More force is acted on in that direction

C) Net force/Mass (-2/4)

5 0

3 years ago

What may result when the energy that builds up at plate boundaries is released because the plates suddenly overcome the force of

Arlecino [84]

It has to be Earthquake

4 0

2 years ago

Read 2 more answers

A strand of 10 lights is plugged into a outlet. How can you determine if the lights are connected in series or parrel

NeTakaya

Answer:

C) Unscrew one light. If the other lights turn off, it's a series circuit.

Explanation:

THIS IS THE COMPLETE QUESTION BELOW;

A strand of 10 lights is plugged into an outlet. How can you determine if the lights are connected in series or parallel? A) Unscrew one light. If the other lights stay on, it's a series circuit. B) Unplug the strand. If the first light stays on, it's a series circuit. C) Unscrew one light. If the other lights turn off, it's a series circuit. D) Cut the strand in half. If the plugged in half stays on, it's a series circuit.

SERIES CIRCUIT

In this circuit, the components there are in the same path, the entire circuit has the same current, each of the components posses different voltage drop. Hence, failure of one components to work, there will be break in entire circuit then other components cease to work.

PARALLEL CIRCUIT

This circuit has equal voltage drop across all the components, any problem in a component will not has effect on other components.

Therefore, if one want to determine if a light connection is in series or in parallel, one of the light can be unplugged if others stop working it means it's series, if other works it's parallel.

5 0

2 years ago