basic formula
Speed Time Formula :
displacement - time formula :
speed - displacement formula :
wherein a is acceleration,
displacement variation - time formula:
< section>Representative adjacent time period equal to the displacement difference, the adjacent T represents the time length of a time period equal
conditions
uniform variable linear motion of the object also complies with the following two:
(1) suffered no resultant force is zero, and remains unchanged;
(2) combined force initial speed along the same line.
Category
at uniform speed linear motion, even if the speed of an object increases with time, this motion is called uniformly accelerated linear motion; if the speed of the object with time decreases uniformly this motion is called uniform deceleration linear motion.
If the direction of velocity acceleration in the same direction (i.e., the same number), it is accelerating; if the opposite (i.e. of opposite sign) to the velocity direction of the direction of acceleration is the deceleration.
law derived
a displacement equation is derived:
(1) Since the speed uniform speed linear motion is uniform changes, so the average speed = (First speed + final velocity) instantaneous speed / 2 = intermediate time
is displaced uniformly variable linear motion = average speed × time, so the
using the displacement formula
(2) using the calculus basic definition, a velocity function (with respect to time) is the derivative of the displacement function of an acceleration function is the derivative on the velocity function written as equation is
Thus
Further there, (p < section>in uniform speed linear motion), apparently at t = 0, s = 0, so that the arbitrary constant C = 0, so there
this is the displacement formula.
(3)
One second displacement:
seconds before the displacement:
can be calculated, two seconds before the displacement of the difference
(4)
simultaneous displacement of formula
Second, the speed formula is derived
(1) intermediate the speed of displacement
Proof: By the displacement of formula
to give
then
finishing square root, to obtain the
(2) intermediate speed time
prove
● formula +
the
proportional
(1) a significant proportion of the relationship
a
a
a
(2) a substantial proportion (initially the speed of uniformly accelerated motion 0)
① second end of the first, second end of the second, ......, n th speed second end than
is derived:
1 seconds ago ②, within the first two seconds, ... ..., displacement ratio of n seconds before the
is derived:
③ a first inner t, the second t, ......, the n-th T (the same time) ratio displacements
is derived:
④ the front 1x, front 2x, before 3x ......, than the time
nx before deriving the desired displacement:
⑤ by the 1st s, 2nd s, third s, ......, n th s (equal to the displacement by continuous) than the time required
is derived:
typical applications
freefall
< b> a, the concept
object only by gravity falling motion from rest.
1, the kinematic characteristics: its size, direction does.
2, the mechanical characteristics: only by gravity in vacuo and the object, or in the air, the air resistance is small suffered object, and the object can be neglected compared to gravity.
3, nature of the movement: the free fall is the initial velocity of zero uniformly accelerated linear motion. Therefore, all laws and uniform linear motion transmission zero initial velocity ratio between the various uniformly accelerated linear motion can be used in free fall.
4, the acceleration of free fall: in the same place, all the objects in a free fall acceleration are the same, this is called gravitational acceleration, expressed in g, the different latitude on the earth, a different value of g. Which is a vertically downward direction. When taking 9.8
II Law
is zero initial velocity in free fall, g is the acceleration rate of the uniform linear motion, the movement of which follows:
1, three basic formula:
2, three special formula:
(1) in successive equal time difference within (T) is a constant displacement value, i.e.
(2) within a certain period of time intermediate First the instantaneous speed equal to the average velocity of this time, i.e.,
instantaneous speed (3) the displacement of certain intermediate position
3, four ratio equation (see the above proportional relationship)
on the vertical projectile motion
object having upward vertical initial velocity, acceleration of gravity g is always uniform transmission of motion, it can be divided into uniform deceleration at the time of dropping and throwing two of the process of free fall. It is the initial velocity
formula
(in
(1)
(2)
(3)
(4) < section>
(5) vertical parabolic time required to reach the maximum height of the
NOTE: may be the rising process