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3 years ago

A person uses 750 kcal on a long walk calculate the energy used for the walk in kilojoules

1 answer:

6 0

Basically, this problem asks you to convert kilocalories (kcal) to kilojoules (kJ). Both are units of energy. To convert kcal to kJ, the equivalence is: 1 kcal = 4.184 kJ. Through dimensional analysis, the solution is as follows:

750 kcal * 4.184 kJ/1 kcal = 3,138 kJ

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A 0.30-kg object connected to a light spring with a force constant of 22.6 N/m oscillates on a frictionless horizontal surface.

gtnhenbr [62]

Answer:

(a) vmax = 0.34m/s

(b) v = 0.13m/s

(d) x = 0.039m

Explanation:

Given information about the spring-mass system:

m: mass of the object = 0.30kg

k: spring constant = 22.6 N/m

A: amplitude of the motion = 4.0cm = 0.04m

(a) The maximum speed of the object is given by the following formula:

$v_{max}=\omega A$ (1)

w: angular frequency of the motion.

The angular frequency is calculated with the following relation:

$\omega=\sqrt{\frac{k}{m}}$ (2)

You replace the expression (2) into the equation (1) and replace the values of the parameters:

$v_{max}=\sqrt{\frac{k}{m}}A=\sqrt{\frac{22.6N/m}{0.30kg}}(0.04m)=0.34\frac{m}{s}$

The maximum speed of the object is 0.34 m/s

(b) If the object is compressed 1.5cm the amplitude of its motion is A = 0.015m, and the maximum speed is:

$v_{max}=\sqrt{\frac{22.6N/m}{0.30kg}}(0.015m)=0.13\frac{m}{s}$

The speed is 0.13m/s

(c) To find the speed of the object when it passes the point x=1.5cm, you first take into account the equation of motion:

$x=Acos(\omega t)$

You solve the previous equation for t:

$t=\frac{1}{\omega}cos^{-1}(\frac{x}{A})\\\\\omega=\sqrt{\frac{22.6N/m}{0.30kg}}=8.67\frac{rad}{s}\\\\t=\frac{1}{8.67}cos^{-1}(\frac{1.5cm}{4.0cm})=0.13s$

With this value of t, you can calculate the speed of the object with the following formula:

$v=\omega Asin(\omega t)\\\\v=(8.67rad/s)(0.04m)sin((8.67rad/s)(0.13s))=0.31\frac{m}{s}$

The speed of the object for x = 1.5cm is v = 0.31 m/s

(d) To calculate the values of x on which v is one-half the maximum speed, you first calculate the time t:

$\frac{v_{max}}{2}=\omega A sin(\omega t)\\\\t=\frac{1}{\omega}sin^{-1}(\frac{v_{max}}{2\omega A})\\\\t=\frac{1}{8.67rad/s}sin^{-1}(\frac{0.13m/s}{2(8.67rad/s)(0.04m)})=0.021s$

The position will be:

$x=Acos(\omega t)=0.04mcos((8.67rad/s)(0.021s))=0.039m$

The position of the object on which its speed is one-half its maximum velocity is 0.039

5 0

3 years ago

NEED HELP

aniked [119]

Answer:

I = 0.25 [amp]

Explanation:

To solve this problem we must use ohm's law which tells us that the voltage is equal to the product of the current by the resistance.

V = I*R

where:

V = voltage [Volt]

I = amperage or current [amp]

R = resistance [ohm]

Since all resistors are connected in series, the total resistance will be equal to the arithmetic sum of all resistors.

Rt = 2 + 8 + 14

Rt = 24 [ohm]

Now clearing I for amperage

I = V/Rt

I = 6/24

I = 0.25 [amp].

5 0

3 years ago

Finally, the switch on the electromagnet is reopened. The magnitude of the external magnetic flux through the wire loop ______ (

Maksim231197 [3]

Answer:

B, B (decreases, a clockwise)

Explanation:

Finally, the switch on the electromagnet is reopened. The magnitude of the external magnetic flux through the wire loop <u>decreases</u>, and there is <u>a clockwise</u>, current induced in the loop (as seen from the left).

7 0

2 years ago

A circular pizza into 3 equal parts, one piece of pizza is taken out. Estimate the degree measure of the single piece of pizza a

seropon [69]

Answer:

A circular pizza has a angle of 360 degrees. When you cut it into 3 equal pieces you divide 360 by 3,you get 120 degrees. And following the conversion of 120 degree into radian you get 2pie/3 radians.

6 0

2 years ago

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What happens to atoms as you move across the periods on the periodic table?

Alex_Xolod [135]

As you move across a period, the atomic mass increases because the atomic number also increases. When the atomic number increases, this means that there are more protons and neutrons that add to the atomic mass of an atom

3 0

2 years ago