I have been working on the problem below, but I could not get the correct answer

ID: 1980448 • Letter: I

Question

I have been working on the problem below, but I could not get the correct answer..

shown below. The projectile moves in the gravitational field of the Earth. Find the angular momentum of

the projectile about the origin when the particle is at at the highest point of its trajectory . (Use the

following as necessary: vi, , m, and g for the acceleration due to gravity.)

So, at the highest point,

x = vi * cos* t

y = vi * sin * t - (1/2) g * t^2

vx = vi * cos

vy = 0

t = vi * sin / g

correct?

Then,

L = m r × v = m (x vy – y vx)

Since vy = 0

L = -m y vx

Is it correct?

yes you are correct. you can directly write it right away though..