answer:
To find out how long it will take for the projectile to travel 21 km downrange, we need to break down the motion of the projectile into its horizontal and vertical components.
First, let's find the horizontal component of the projectile's velocity. The horizontal component is given by the equation:
horizontal velocity = initial velocity * cos(angle)
Plugging in the values given:
horizontal velocity = 840 m/s * cos(60°)
Simplifying:
horizontal velocity = 840 m/s * 0.5
horizontal velocity = 420 m/s
Next, we can find the time it takes for the projectile to travel 21 km downrange using the horizontal velocity:
distance = velocity * time
21,000 m = 420 m/s * time
Solving for time:
time = 21,000 m / 420 m/s
time = 50 seconds
Therefore, it will take the projectile 50 seconds to travel 21 km downrange
real