Question

a projectile is thrown with speed u = 20 m/s at an angle 30 degree with horizontal from the top of building 40 m high. the horizontal range of projectile is

Answer 1

u = 20 m/s.    Ф = 30°.   To find x when y = - 40 m.

Equation of projectile:  y = x tan Ф - g x² Sec² Ф / 2u²
y = -40 m when the projectile hits the ground.

y = - 40 = x /√3 - (10 * 4/3 * 1/2 * 1/20² ) x² 
x² - 20√3 x - 2400 = 0
x = 10√3 + √2700  = 40 √3 meters

Range = 40 √3 m

Answer 2

Answer:

40√3

Explanation:

see the attachment