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LESSON NOTES

EQUATIONS OF MOTIONS FOR FREELY FALLING OBJECTS:
• For a freely falling body, the following equations of motion hold good:

1
2
2
• (i) v = u + gt (ii) s = ut + gt (iii) v - u = 2gs
2
2
• When a body falls freely under the action of gravity, its velocity increases and the
value of g is taken positive.
• When a body is thrown vertically upward, its velocity decreases and the value of

g is taken negative.
Formulae Used

• 1. For a freely falling body, the equations of motion are

1
2
2
2
• (i) v = u + gt (ii) s = ut + gt (iii) v - u = 2gs
2
• 2. For a body falling freely under the action of gravity, g is taken positive.
• 3. For a body thrown vertically upward, g is taken negative.
• 4. When a body is just dropped, u = 0

• 5. For a body thrown vertically up with initial velocity u,
2
• (i) Maximum height reached, h = u
2g

u
• (ii) Time of ascent = Time of descent =
g
2u
• (iii) Total time of flight =
g
• (iv) Velocity of fall at the point of projection = u

• (v) Velocity attained by a body dropped from height h, v = √2gh.