<span>1.) It is 6.00km from your home to the physics lab. As part of your physical fitness program, you could run that distance at 10.0km/hr (which uses up energy at the rate of 700W ), or you could walk it leisurely at 3.00km/hr (which uses energy at 290 W).
A.)Which choice would burn up more energy?
running or walking?
b.)How much energy (in joules) would it burn?
c.)Why is it that the more intense exercise actually burns up less energy than the less intense one?
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Answers
billrussell42
Best Answer: running, at 10 km/hour for 6 km is
6 km / 10 km/hour = 0.6 hour or 36 min
energy used is 700 watts or 700 joules/s x 36 min x 60s/min = 1.512e6 joules or 1.5 MJ
walking, at 3 km/hour for 6 km
6 km / 3 km/hour = 2 hour or 120 min
energy used is 290 watts or 290 joules/s x 120 min x 60s/min = 1.872e6 joules or 1.8 MJ
C) should be obvious
PS, this has nothing to do with potential energy.
billrussell42 · 5 years ago
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Simon van Dijk
I assume the watt consumption is per hour. Then running 6km at 10.0 km/h results in 700*6/10 = 420 w.h and walking in 290*6/3 = 580 w.h So walking would burn up more energy (kwh)
b) 1 kilowatt hour = 3 600 000 joules
so 420 wh = 0.42 kwh = 1.51.10^6 joule
c) when you put more effort in making the distance your energy is used more efficient.
Simon van Dijk · 5 years ago
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The initial force of motion and inward acting force
Answer: mass for Pyrex glass 84.21g
mass for sand 61.6g
mass for ethanol 41.32g
mass for water 62.07g
Explanation
By definition specific heat is the amount of heat required to change the temperature of 1 kg mas by 1°C
Q=mcΔT is formula for specific heat
Q is heat transfer
m is mass
ΔT is change in temperature
c is specific heat
c of Pyrex glass= 0.75 j/g°C
c of sand = 0.84 j/g°C
c of ethanol= 2.42 j/g°C
c of water = 4.18 j/g°C
now we will make M(mass) the subject, so equation becomes
m=Q/cΔT
for
pyrex glass T<em>f=</em>55.4°C
m=1920/(55.4-25)*0.75
m=84.21g {after cutting J(joules) and °C we are left with g(grams)}
for
sand T<em>f</em>=62.1°C
m=1920/(62.1-25)*0.84
m=61.6g {after cutting J(joules) and °C we are left with g(grams)}
for
ethanol T<em>f</em>=44.2°C
m=1920/(44.2-25)*2.42
m=41.32g {after cutting J(joules) and °C we are left with g(grams)}
for
water T<em>f=</em>32.4°
m=1920/(32.4-25)*4.18
m=62.07g {after cutting J(joules) and °C we are left with g(grams)}
i hope you understand the solution, thank you.
Answer:
See below ~
Explanation:
An object will sink in water when its density is greater than that of water, which is 1 g/cm³.
Volume of the box is <u>1331 cm³</u>. (11³)
Maximum mass of sand will be 1331 g. [because 1331/1331 = 1 g/cm³]
- Volume of sand = Mass of sand / Density of sand
- Volume (sand) = 1331/3.5
- Volume (sand) = 380.29 cm³
If the volume of sand is <u>greater than 380.29 cm³</u>, the box will sink in water.
