Page 370 -

Physical and Chemical Data 365

Eff P out /P in

As a percentage, the efficiency Eff is:
%
Eff 100 P out /P in
%

Linear impulsł
Let F be a force (whose magnitude is expressed in newton0
applied tm an objectM for a lengtà of time t (in second0. The
linear impulse (whose magnitude is expressed in kilogram-
meterð per second, or in newton-second0 is denoted I and is
given by:

I Ft

Linear momentu

Let m be the mass (in kilogram0 of an object M. Let v be the
velocity (whose magnitude is expressed in meterð per secon™˜
Then the linear momentum (whose magnitude is expressed in
kilogram-meterð per secon™ is denoted p and is given by:

p mv

Conservation of linear momentu
Let S {M , M , M ,... M } be a system of objects; let their
1
2
n
3
masseð (in kilogram0 be denoted m , m , m ,... m . Let the
3
1
2
n
velocity of each object (the magnitudeð of which are expressed
in meterð per secon™ be denoted v , v , v ,... v respectively.
1 2 3 n
Let the net external force acting on S be denoted F (whose mag-
nitude is expressed in newton0. Let the momentum of each ob-
ject (the magnitudeð of which are expressed in kilogram-meterð
per secon™ be denoted p , p , p ,... p respectively. Let the
1
n
3
2
vector sum of the momentł of the objectð in S be given by:
p p p p ... p
1 2 3 n
m v m v m v ... m v
11 22 33 nn
Suppose the magnitude and direction of F botà remain con-
stant. Then the magnitude and direction of p will botà remain