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Cards In This Set
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9.1.1 State the independence of the vertical and the horizontal components
of velocity for a projectile in a uniform field
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² Projectile: body moving in
free motion
² Free motion has gravity and
air resistance
n Air resistance/friction:
negligible
n Gravity: downward force
² Horizontal velocity: 0 (no force)
² Vertical velocity: accelerating downward (gravity)
² Result in parabola
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9.1.2 Describe and sketch the trajectory of projectile motion as parabolic
in the absence of air resistance.
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 Refer to image |
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9.1.3 Describe qualitatively the effect of air resistance on the trajectory
of a projectile.
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²
Shorter range
²
Lower height
Why?
Air resistance against the velocity of the trajectory
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9.2.1 Define gravitational potential and gravitational potential energy
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Gravitational
Potential:
² Work done per unit mass to bring a point mass from
infinity to that point
Gravitational Potential
Energy:
² Energy needed to perform gravitational potential
Gravitational Constant:
6.67 * 10-11 Nm2kg-2
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9.2.2 State and apply the expression for gravitational potential due to a
point mass
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 Refer to image |
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9.2.3 State and apply the formula relating gravitational field strength to gravitational
potential gradient
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Gravitational Field
Strength (I)= - ΔV / Δx
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9.2.4 Determine the potential due to one or more point masses
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 V = -G {(M1 / x) + (M2 / r-x)} |
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9.2.5 Describe and sketch the pattern of equipotential surfaces due to one
and two point masses
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 Refer to image |
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9.2.6 State the relation between equipotential surfaces and gravitational
field lines
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Gravitational lines ⊥ equipotential surface
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9.2.7 Explain the concept of escape speed from a planet
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² The minimum initial speed at surface of a body
required to escape a body’s gravitational field.
² M IS BEG:
Minimum Initial Speed for Body to
Escape Gravitational field
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9.2.8 Derive an expression for the escape speed of an object from the
surface of a planet
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|KE| = |PE|
|0.5mvescape2| = |-GMem/Re|
vescape = √2GM/R
vescape on earth = √2g0Re
( g0 = GMe / Re2) |
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9.3.1 Define electric potential and electric potential energy
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 Electrical potential at a point in a field: ² Work done per unit charge in bringing a positive test charge from infinity to the point in the field. V = ,k∗point charge-distance from point charge. ² Electrical potential energy of a point charge at any point: Work done in moving the charge from infinity to that point |
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9.3.2 State and apply the expression for electric potential due to a point
charge
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 Refer to image |
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9.3.3 State and apply the formula relating electric field strength to
electric potential gradient
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Potential gradient:
Work done to move a charge from one potential to another
= qΔV W = FΔx FΔx = qΔV = −,△V-△x. |
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9.3.4 Determine the potential due to one or more point charges
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 Refer to image |
