As given the formula of range is

now for the maximum range


now for half of this maximum range we will have


now from above we have

so two possible values for above is given as

so above two angle we will have half of maximum range
Hi there!
Using Hooke's Law:

F = Force (N)
k = Spring constant (N/m)
x = displacement from equilibrium
We are given the force and displacement, so solve for 'k':
