5 projectile motion

mass & weight

weight: force acting on a body due to gravitational field

apparent weightlessness: due to absence of forces acting on a body by its contact with another body

projectile motion

• constant acceleration, velocity not

• at max height, Vy=0, Vx not, hence V is never 0

falling with drag force

1. from rest

• Fr = -mg

• a = g, downwards

• v inc downwards

2. drag force introduced

• v inc, Fdrag inc

• Fr dec

• a dec, but still downwards

• v still inc downwards, rate of inc decreases

3. Fdrag = W

• v constant (terminal v)

• Fr = 0

• a = 0

explaining asymmetrical parabolic path

1. horizontal direction, ball experiences drag force, horizontal speed dec, shorter range

2. when ball rises, there is WD against air resistance, by PCOE, max height lower

3. when ball rises, net acceleration downwards > g as air resistance is in same direction as Fg, vert speed decreases to 0 faster, rchs mac height faster, max height displaces to left

4. hence path is asymmetrical