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:
.
W = Fd = 4(2100) = 8400 J
So the answer is A) 8400 J
I was just rewriting my notes on the work lesson I did in class today, so I saw this question at the perfect time!! :)
Hope it helps!! :)
Answer:
The vertical distance that the ski jumper fell is 417.45 m.
Explanation:
Given;
initial horizontal velocity of the jumper,
= 26 m/s
horizontal distance of the jumper, dx = 240 m
The time of the motion is given by;
dx = Vₓt
t = dx / Vₓ
t = 240 / 26
t = 9.23 s
The vertical distance traveled by the diver is given by;

initial vertical velocity,
, = 0

Therefore, the vertical distance that the ski jumper fell is 417.45 m.
Answer:
time = 8.3333 minutes.
Explanation:
distance between earth and sun = 1.5 * 
speed of light = 3* 
convert the distance unit from km to m so we can have uniform units.
distance between earth and sun = 1.5 *
m
distance between earth and sun = 1.5 *
m
speed = distance /time
time = distance / speed
time = 

time =500 sec
time = 500/60 minutes
time = 8.3333 minutes.