Not sure where you're getting your equations from. The range of the projectile is given by
The time to impact is given by
Finally, you're going to have that
Solve these equations for .
A particle of Q is projected from A at ground level. After 4 seconds the particle strikes the ground again at B where AB = 200m. Calculate the initial velocity of Q.
Sub 1 in 2
is everything correct?
thanks for your help!
Ok. Here's an explanation of all symbols in these equations:
is the horizontal distance along the ground between the launch point and the striking point. Otherwise called the range.
is the magnitude of the initial velocity. Also called the initial speed of the projectile. This is a scalar quantity, and is equal to the magnitude of the initial velocity vector.
is the acceleration due to gravity.
is the angle of elevation of the projectile when launched. It's the angle between the horizontal and the initial velocity vector.
is the amount of time it takes the projectile to strike the ground after having been launched.
is the component of the initial velocity in the -direction.
There's a notational error in my equations:
, not . Sorry about that. I've fixed that. Does this help explain things?