physics
posted by yelya .
A ball launched from ground level lands 2.15 s later on a level field 50 m away from the launch point. Find the magnitude of the initial velocity vector and the angle it is above the horizontal. (Ignore any effects due to air resistance.)

u = constant horizontal speed = 50/2.5 = 20 m/s
v = vi  9.8 t
at top of arc, t = 2.5/2 = 1.25 seconds and v = 0
so at top
0 = vi  9.8 (1.25)
so
vi = 12.25
so speed at start = sqrt (20^2 + 12.25^2)
= sqrt(400+ 150) = sqrt 550 = 23.5 m/s
tan angle = 12.25/20
so
angle = 31.5 degrees
Respond to this Question
Similar Questions

Physics
A soccer player kicks a ball from the ground into the goal, which is located 17 meters away on the level playing field. The ball leaves the ground at an initial speed of 18m/s and at an initial angle above the horizontal of 23 degrees. … 
Physics
A ball launched from ground level lands 2.7 s later on a level field 50 m away from the launch point. Find the magnitude of the initial velocity vector and the angle it is above the horizontal. (Ignore any effects due to air resistance.) … 
physics
A ball launched from ground level lands 3 s later on a level field 48 m away from the launch point. Find the magnitude of the initial velocity vector and the angle it is above the horizontal. (Ignore any effects due to air resistance.) 
Physics
A ball thrown into the air lands on the same horizontal level, 31 m away, and 2.65 s later. Find the magnitude of the initial velocity. 
physics
A projectile is launched at an angle of 58.5 degrees above the horizontal and lands at the same level from which it was launched 3.88 seconds later. what is the magnitude of the initial velocity? 
johnny
A projectile is launched over level ground at a launch angle of 70o with an initial velocity vo. At some later time while the projectile is on its way to the peak in its trajectory, its velocity vector makes an angle of 50o with respect … 
physics
A projectile is launched over level ground at a launch angle of 70o with an initial velocity vo. At some later time while the projectile is on its way to the peak in its trajectory, its velocity vector makes an angle of 50o with respect … 
Physics
At time t = 0, a projectile is launched from ground level. At t = 2.00 s, it is displaced d = 53 m horizontally and h = 54 m vertically above the launch point. What are the (a) horizontal and (b) vertical components of the initial … 
Physics
A projectile is launched at ground level with an initial speed of 51.5 m/s at an angle of 35.0° above the horizontal. It strikes a target above the ground 2.50 seconds later. What are the x and y distances from where the projectile … 
physics
A projectile is launched at ground level with an initial speed of 56.0 m/s at an angle of 35.0° above the horizontal. It strikes a target above the ground 2.90 seconds later. What are the x and y distances from where the projectile …