Question

A water balloon is launched with an initial speed of 40 m/s at 60 degrees above the horizontal. A tall building is 40 m from the launch site. Neglect air resistance and use g = 10 m/s^2.

(numbers 8-11) A water balloon is launched with an initial speed of 40 m/s at 60 degrees above the horizontal. A tall building is 40 m from the launch site. Neglect air resistance and use g 10 m/s2 8. How much time does it take for the water balloon to hit the building? a) 2.0 s b) 2.4 s c) 2.8 s d) 3.2 s e) 3.6s ,D 9. At what height above ground level does the water balloon hit the building? a) 49.3 m b) 45.3 m c) 41.3 m d) 37.3 m e) 33.3 m 10. How fast is the water balloon moving as it hits the building? a) 33.8 m/s b) 30.8 m/s c) 27.8 m/s d) 24.8 m/s e) 21.8 m/s

Answer 1

Along Horizontal v_x = v_0 x = 40 cos 60 degree, a_x = 0 x = 40 m x = v_0 x t + 1/2 a_x t^2 40 = 40 cos 60 degree xt rightwardsdoublearrow t = -2 s a Along vertical v_0 y = 40 sin 60 degree, a_y = -9.8 m/s^2 y = v_0 y t + 1/2 a_y t^2 = 40 sin 60 degree times 2 - 1/2 times 9.8 times 2^2 = 49.7 m if a-y = -10 m/s^2 then y = 49.3 m a v_y = v + 0 y + a_y t = 40 sin 60 - 10 times 2 = 14.96 m/s v = squareroot v_x^2 + v_y^2 = 24.8 m/s d