Answer:
Initial speed = v₁ = 13.86 m/s
Step-by-step explanation:
This problem is related to the projectile motion. Projectile motion is a two dimensional motion having horizontal and vertical component. Horizontal component of the velocity remain constant throughout his motion while vertical component vary with time.
Given data :
Mass = m = 78 g
Angle = θ = 45.3°
Range = R = 19.6 m
Gravitational acceleration = g = 9.8 m/s²
Initial velocity = v₁ = ?
Using the formula of range of the projectile
θ


v₁² = 192.09
v₁ = 13.86 m/s