A projectile is launched from the foot of an inclined plane which makes an angle of 30 degrees with the horizontal. The projectile's initial velocity is 20 m/s at an angle of 45 degrees with the inclined plane. Neglecting air resistance, the time taken by the projectile to hit the inclined plane is closest to:
1.0 s
1.5 s
2.0 s
2.5 s
The projectile's motion can be divided into two parts:
Horizontal motion and vertical motion.
In the horizontal direction, the projectile moves with a constant velocity of .
In the vertical direction, the projectile experiences a constant acceleration due to gravity of .
Let's consider the vertical motion of the projectile.
The initial vertical velocity of the projectile is .
The time taken by the projectile to hit the inclined plane can be found using the equation:
where is the vertical displacement of the projectile, is the initial vertical velocity of the projectile, is the acceleration due to gravity, and is the time taken by the projectile to hit the inclined plane.
The vertical displacement of the projectile can be found using the angle of the inclined plane:
where is the horizontal displacement of the projectile.
The horizontal displacement of the projectile can be found using the time taken by the projectile to hit the inclined plane and the horizontal velocity of the projectile:
Substituting these equations into the first equation, we get
Simplifying and solving for , we get:
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