The magnitude of the velocity of a projectile when it is at its maximum height above ground level is 15 m/s. (a) What is the magnitude of the velocity of the projectile 1.2 s before it achieves its maximum height? (b) What is the magnitude of the velocity of the projectile 1.2 s after it achieves its maximum height? If we take x = 0 and y = 0 to be at the point of maximum height and positive x to be in the direction of the velocity there, what are the (c) x coordinate and (d) y coordinate of the projectile 1.2 s before it reaches its maximum height and the (e) x coordinate and (f) y coordinate 1.2 s after it reaches its maximum height?
Xo = 15 m/s = Hor. component of initial
velocity.
Tr = 1.2 + 1.2 = 2.4 s. = Rise time.
Y = Yo + g*Tr = 0.
Yo = -g*Tr = -(-9.8)*2.4 = 23.5 m/s. =
Ver. component 0f initial velocity.
Y = Yo + g*t = 23.5-9.8*1.2 = 11.74 m/s.
a. V = sqrt(Xo^2+Y^2)=sqrt(15^2+11.74^2)
= 19 m/s.
b. Y = Yo + g*t = 0 + 9.8*(2.4+1.2) = 35.28 m/s, Downward.
V = sqrt(15^2+35.28^2) = 38.3 m/s.