students’ learning efficiency. Compared with traditional
multimedia devices, mobile smart terminals can
effectively meet the individual needs of students, allow
students to actively participate in school classrooms, and
better achieve the goal of high school physics teaching.
For example, when explaining
the law of universal
gravitation, students can collect learning tasks from
teachers through mobile smart terminals such as smart
tablets in their hands, and
then write the derivation
process of the formula on the smart tablet. At the same
time, teachers can randomly project students’ tablet
content, share learning results with students, and allow
students to answer actively, understand the process of
students’ thinking. Teachers can summarize and explain
the correct derivation process, so as to better achieve high
school the goal of physics teaching [3].
Prove: There are two isolated objects whose masses
are M and m respectively, the distance between them is r,
and the period of m making
uniform circular motion
around M is T.
The universal gravitation of M on M F provides
centripetal force as follows.
r
T
m
F
2
2
=
(1)
By Kepler’s third law:
k
T
r =
2
3
(2)
By (1)(2), it can get:
( )
2
2
2
r
k
m
F
=
namely F∝
2
r
m
(3)
According to Newton’s third law, the gravitational
attraction of M on M is also F, and has the same property.
So the gravitational attraction of m with respect to
M is F∝
2
r
M
(4)
Synthesis (3)(4):
F∝
2
r
Mm
(5)
Law of
universal gravitation
2
r
Mm
G
F =
(6)
(G is gravitational constant.)
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