The initial velocity in projectile motion can be calculated using the formula v0 = v*cos(theta), where v is the initial speed and theta is the angle of launch.
The equations for solving projectile motion problems in one line are x = x0 + v0*t*cos(theta) and y = y0 + v0*t*sin(theta) - 0.5*g*t2, where x and y are the horizontal and vertical positions, x0 and y0 are the initial positions, v0 is the initial velocity, t is the time, theta is the angle of launch, and g is the acceleration due to gravity.
The range of a projectile can be found using the formula R = v02*sin(2*theta)/g, where R is the range, v0 is the initial velocity, theta is the angle of launch, and g is the acceleration due to gravity.
Yes, the same equations can be used to solve projectile motion problems in two lines. However, the initial velocity and angle of launch may need to be calculated separately using other equations.
To take air resistance into account in projectile motion problems, you can use the formula v = v0*e-kt/m, where v is the velocity at any time, v0 is the initial velocity, k is a constant, t is the time, and m is the mass of the object. This equation can be incorporated into the equations for solving projectile motion problems.