Answer:
In SI units 98.1 N, 16.24 N
English units 22.053861 lbf, 3.6509144 lbf
Explanation:
g = Acceleration due to gravity
m = Mass = 10 kg
Weight on Earth
Converting to lbf
On Moon
Converting to lbf
In SI units 98.1 N, 16.24 N
English units 22.053861 lbf, 3.6509144 lbf
Answer:
Approximately 
. (Assuming that 
, and that the tabletop is level.)
Explanation:
Weight of the book:
.
If the tabletop is level, the normal force on the book will be equal (in magnitude) to weight of the book. Hence, 
.
As a side note, the 
and 
on this book are not equal- these two forces are equal in size but point in the opposite directions.
When the book is moving, the friction 
on it will be equal to
, the coefficient of kinetic friction, times
, the normal force that's acting on it.
That is:
.
Friction acts in the opposite direction of the object's motion. The friction here should act in the opposite direction of that 
applied force. The net force on the book shall be:
.
Apply Newton's Second Law to find the acceleration of this book:
.
Answer:
E means energy
M= Mass
C=speed of light squared (the exponent means squared)
Energy to lift something =
(mass of the object) x (gravity) x (height of the lift).
BUT ...
This simple formula only works if you use the right units.
Mass . . . kilograms
Gravity . . . meters/second²
Height . . . meters
For this question . . .
Mass = 55 megagram = 5.5 x 10⁷ grams = 5.5 x 10⁴ kilograms
Gravity (on Earth) = 9.8 m/second²
Height = 500 cm = 5.0 meters
So we have ...
Energy = (5.5 x 10⁴ kilogram) x (9.8 m/s²) x (5 m)
= 2,696,925 joules .
That's quite a large amount of energy ... equivalent to
straining at the rate of 1 horsepower for almost exactly an
hour, or burning a 100 watt light bulb for about 7-1/2 hours.
The reason is the large mass that's being lifted.
On Earth, that much mass weighs about 61 tons.
