Question

ball is projected from ground at an angle 45 just clears wall in front if point of projection is phone me the sun the food the fall and ball strikes the ground at a distance of 6 metres on either side of the wall the height of the wall is​

Answer 1

Explanation:

Given Ball is projected from ground at an angle 45 just clears a wall in front. If point of projection is 4 m from the foot of the wall and ball strikes the ground at a distance of 6 metres on either side of the wall the height of the wall is

• Given angle of projection is 45 degree and point of projection is 4 m.
• Now total distance of wall is 4 + 6 = 10 m  
• We know the formula for range.                    
• So 10 m = u^2 sin 2θ / g                                                              
• Now θ = 45 degree, so 2 θ = 2 x 45 = 90
• So sin 90 = 1
• So u^2 / g = 10 m
• Or u = 10 m/s
• Now we need to find the height of the wall, so equation of projection will be
• So y = x tan θ – 1/2 gx^2 / 2u^2 cos^2 θ
•        = 4 tan 45 – 1/2 x 10 x 16 / 2 x 100 x cos^2 45 (cos^2 45 = (1/√2)^2 = 1/2  
•         = 4 x 1 – 1/2 x 10 x 16 / 2 x 100 x 1/2  
•          = 4 – 0.8

Or y = 3.2 m

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