In a gear train with two gears, the gear ratio is defined as follows
where

is the angular velocity of the input gear while

is the angular velocity of the output gear.
This can be rewritten as a function of the number of teeth of the gears. In fact, the angular velocity of a gear is inversely proportional to the radius r of the gear:

But the radius is proportional to the number of teeth N of the gear. Therefore we can rewrite the gear ratio also as
Answer:0.25 kg-m/s
Explanation:
Given
mass of blob 
initial velocity 
time of collision 
we know Impulse is equal to change in momentum
initial momentum 

Final momentum 
as final velocity is zero
Impulse 


Answer:
We know there's two forces acting on a book while it sits on a table:the force of gravity pulling it down, and the normal force of the table acting upward on the book. The book isn't accelerating while it sits there. That's because the weight of the book is being counteracted by the normal force of the table.
Explanation:
There are two forces acting upon the book. One force - the Earth's gravitational pull - exerts a downward force. The other force - the push of the table on the book (sometimes referred to as a normal force) - pushes upward on the book.
Answer:

Explanation:
= Length of wire = 65 m
= Initial current = 1.8 A
= Final current = 2.9 A
We know

and


so

The length of the wire remaining on the spool is
.
Beta decay is very complex phenomena in natural radioactive decay. There are 3 types of Beta decay.
B+ decay (Beta plus or Beta positive or positron decay):
is the conversion of a proton into a neutron plus a positron and an electron neutrino.
B- decay (Beta negative or Beta nought):
is the conversion of a neutron into a proton plus an electron and a electron antineutrino.
Note: a positron is the a positive electron or the antiparticle of the electron.
Hope it helps