Answer:
31.55 m/s
Explanation:
Let the initial velocity of the arrow is u metre per second.
Angle of projection, θ = 40 degree
range = 100 m
Use the formula for the range.
100 = u^2 Sin(2 x 40) / 9.8
100 x 9.8 = u^2 Sin 80
u^2 = 995.11
u = 31.55 m/s
solution
Given
mass= 20kg
velocity =3m/s
K.E=?
K.E= ½mv²
½×20×3²
½×20×9
½×180
90 J