Question

figure shows a projectile trown with speed u=20 m/s at an angle 30 with horizontal from the top of a building 40m high. then the horizontal rqnge of projectile is?

Please tell with proper explanation

Answer 1

Answer:

range=2usin30*ucos30÷g

=2*20*1/2*20√3/2÷10

=20√3

Answer 2

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 metres