Question

While out on your 3rd floor apartment balcony, you notice someone drop a 8.0 kg ball from rest from the roof of the 5 story building across the street. You know that the two identical buildings are 34 m apart, and have floors that are 5.0 m tall. The first floor is at ground level.

m = 8.0 kg

d = 34 m

h = 5.0

(a) determine the magnitude of the angular momentum of the ball, in kilogram meters squared per second, as observed by you immediately after it is dropped.

(b) determine the magnitude of the angular momentum of the ball, in kilogram meters squared per second, as observed by you as it passes the floor of the 4th floor balcony of the other building.

(c) determine the magnitude of the angular momentum of the ball, in kilogram meters squared per second, as observed by you as it passes the floor of the 3th floor balcony of the other building (directly across from you).

(d) determine the magnitude of the angular momentum of the ball, in kilogram meters squared per second, as observed by you as it passes the floor of the 2th floor balcony of the other building.

(e) determine the magnitude of the angular momentum of the ball, in kilogram meters squared per second, as observed by you immediately before it hits the ground, at the bottom of the first floor..

Answer 1

a) L = m*v*d*sin(90)

= 0 (since v = 0) <<<<<<<<<<---------------------Answer

b) speed of ball at it passes the floor of the 4th floor balcony of the other building, v = sqrt(2*g*(2*h))

= sqrt(2*9.8*(2*5))

= 14 m/s

angular momentum, L = m*v*d*sin(90)

= 8*14*34

= 3808 kg.m^2/s <<<<<<<<<<---------------------Answer

c) speed of ball at it passes the floor of the 3rd floor balcony of the other building, v = sqrt(2*g*(3*h))

= sqrt(2*9.8*(3*5))

= 17.1 m/s

angular momentum, L = m*v*d*sin(90)

= 8*17.1*34

= 4651 kg.m^2/s <<<<<<<<<<---------------------Answer

d) speed of ball at it passes the floor of the 2nd floor balcony of the other building, v = sqrt(2*g*(4*h))

= sqrt(2*9.8*(4*5))

= 19.8 m/s

angular momentum, L = m*v*d*sin(90)

= 8*19.8*34

= 5386 kg.m^2/s <<<<<<<<<<---------------------Answer

e) speed of ball when it hits the ground, v = sqrt(2*g*(5*h))

= sqrt(2*9.8*(5*5))

= 22.1 m/s

angular momentum, L = m*v*d*sin(90)

= 8*22.1*34

= 6011 kg.m^2/s <<<<<<<<<<---------------------Answer