John weighs 200 pounds.
In order to lift himself up to a higher place, he has to exert force of 200 lbs.
The stairs to the balcony are 20-ft high.
In order to lift himself to the balcony, John has to do
(20 ft) x (200 pounds) = 4,000 foot-pounds of work.
If he does it in 6.2 seconds, his RATE of doing work is
(4,000 foot-pounds) / (6.2 seconds) = 645.2 foot-pounds per second.
The rate of doing work is called "power".
(If we were working in the metric system (with SI units),
the force would be in "newtons", the distance would be in "meters",
1 newton-meter of work would be 1 "joule" of work, and
1 joule of work per second would be 1 "watt".
Too bad we're not working with metric units.)
So back to our problem.
John has to do 4,000 foot-pounds of work to lift himself up to the balcony,
and he's able to do it at the rate of 645.2 foot-pounds per second.
Well, 550 foot-pounds per second is called 1 "horsepower".
So as John runs up the steps to the balcony, he's doing the work
at the rate of
(645.2 foot-pounds/second) / (550 ft-lbs/sec per HP)
= 1.173 Horsepower. GO JOHN !
(I'll betcha he needs a shower after he does THAT 3 times.)
_______________________________________________
Oh my gosh ! Look at #26 ! There are the metric units I was talking about.
Do you need #26 ?
I'll give you the answers, but I won't go through the explanation,
because I'm doing all this for only 5 points.
a). 5
b). 750 Joules
c). 800 Joules
d). 93.75%
You're welcome.
And #27 is 0.667 m/s .
Answer:
Explanation:
We shall represent displacement of dog in vector form , in terms of i , j , i representing east and j representing north .
Dog travels 3.5 m south .
Displacement D₁ = - 3.5 j
then dog travels 8.2 m , 23.1 degree north of east
Displacement D₂ = 8.2 cos23.1 i + 8.2 sin23 j
D₂ = 8.2 cos23.1 i + 8.2 sin23.1 j
= 7.54 i + 3.22 j
Third displacement
D₃ = - 15i
Total displacement = D₁ + D₂ + D₃
= - 3.5 j + 7.54 i + 3.22 j -15i
= - 7.46 i - 0.28 j
Magnitude of displacement = √ ( 7.46² + .28²)
= √(55.65 + .08 )
= 7.46 m
b ) Direction of displacement
If Ф be angle , displacement makes with west direction
TanФ = .08 / 55.65 = .00143
Ф = .082 degree south of west or almost west .
From east , this angle = 180 + .082 = 180.082 , counterclockwise .
Answer:
Explanation:
Given
Displacement is 
of Amplitude
i.e. 
, where A is maximum amplitude
Potential Energy is given by
Total Energy of SHM is given by
Total Energy=kinetic Energy+Potential Energy
Potential Energy is 
th of Total Energy
Kinetic Energy is 
of Total Energy
(c)Kinetic Energy is 
Answer:
So then the difference of temperature across the material would be 
Explanation:
For this case we can use the Fourier Law of heat conduction given by the following equation:
(1)
Where k = thermal conductivity = 0.2 W/ mK
A= 1m^2 represent the cross sectional area
Q= 3KW represent the rate of heat transfer
is the temperature of difference that we want to find
represent the thickness of the material
If we solve 
in absolute value from the equation (1) we got:
First we convert 3KW to W and we got:
And we have everything to replace and we got:
So then the difference of temperature across the material would be
Answer:
One end of any bar magnet will always want to point north if it is freely suspended. This is called the north-seeking pole of the magnet, or simply the north pole. The opposite end is called the south pole.
Explanation:
