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gravity slideshow by idrul nafiz
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What is acceleration?What is mass?What is force?
When the ball is release, the ball will reach the ground. Why?
2.8 Understanding
Gravity
Explain and determine the value of acceleration due to gravity
Define gravitational field and gravitational strengthDefine weightSolve problems involving acceleration due to gravity
To study the relationship between acceleration of an object and mass
Material : Water bottle (2)
Conclusion
Both objects reach the bottom at the same timeBoth objects reach the bottom at the same time
The acceleration of an objects does not depend on the massThe acceleration of an objects does not depend on the mass
Definition: Acceleration of an object due to the pull of the gravitational force only.
The value of acceleration due to gravity, g is 9.8 ms-2
An object is falls freely under the influence of gravitational force only
Definition: Region in which an object experiences a force due to gravitational attraction
Any massive object that enters this field will experience a force of attraction
This field will get weaker the further you go out from the centre of earth
Earth: half sizeEarth: half size
Earth: Half Size
GRAVITATIONAL FIELD
Gravitational field strength is defined as the gravitational force per unit mass
Gravitational field strength of the earth is 9.8 N kg-1
Gravitational field strength of moon is 1.6 N kg-1
m
Fg
1 Nkgkg
N
A ball falls vertically a distance of 125 m to the ground. Using g = 9.8 ms-2 ; calculate:
a)Time the ball takes to fall the first 25m
b)Time the ball takes to reach the ground
c)The velocity of ball before it hits the ground
Define: Gravitational force acting on a body
Where mass is m and g is gravitational field strength or the acceleration due to gravity
Unit = N
mgW
What is Ali’s weight on the earth and moon if its mass is 70kg?Use g earth = 9.8 ms-2 and g moon = 1.6 ms-2
Question time…
1 23 4
Question 1Our bodies are pulled down to the earth's surface by
A.Newton’sB.WeightC.Gravity
Question 2Object with different mass have ……… acceleration due to gravity
A.DifferenceB.SameC.Zero
Question 3Value of acceleration due to gravity on earth is 9.8 ms-1
A.TrueB.False
Question 4If an object fall with an acceleration due to gravity, the velocity of the object must……
A.Be constantB.Continuously change by the same amount each second
C.Continuously change by varying amount each second
D.Continuously decrease
Acceleration due to gravity is the acceleration of an object due to the pull of the gravitational force
Gravitational field is the region in which an object experiences a force due to gravitational attraction
Free fall is an object falls under the influence of gravitational force only
Gravitational field strength is the gravitational force per unit mass
Weight is the gravitational force acting on a body