Projectile Motion

Question 1

Free fall

Answer 1

Only force is by earth on object, weight
Resultant force would be = weight
acceleration = 9.81 vertically downwards

Question 2

Why is trajectory of object in projectile motion Parabola

Answer 2

Projectile motion deals with motion of body when it undergoes uniform velocity in horizontal direction. Since only force on object during motion is force of gravity, resultant force which object experiences will be due to own weight. Hence acc is always only constant -9.81 ms^-2 vertically downwards, no acc in horizontal direction

Question 3

Equations for solving projectile motion

Answer 3

Horizontal
acc= 0
velocity = u
displacement = ut

Vertical
acc = -g
velocity = u + (-gt)
displacement = ut + 1/2 at^2
Time independent,
v2 = u2 + 2(-g)s

velocity at any instant
= root(vx2 + vy2)

in direction
theta = tan^-1 (vy/vx)

max height
v=vx
if same starting and end
displacement = 0