A projectile is launched from ground level at an angle of 70.0° above horizontal with a speed of 50.0 m/s. If the projectile is moving over level ground, how far way from the launch position does it contact the ground?
A)164 m
B)54.2 m
C)203 m
D)102 m
E)12.4 m

Question

Quizplus · Accepted Answer

The correct answer is A.The horizontal component of the velocity is:$$v_{x} = v \cos 	heta = 50.0 \ m/s \cos 70.0° = 16.4 m/s$$The vertical component of the velocity is:$$v_{y} = v \sin 	heta = 50.0 \ m/s \sin 70.0° = 46.9 m/s$$The time it takes for the projectile to reach the ground is:$$t = \frac{2v_{y}}{g} = \frac{2(46.9 \ m/s)}{9.8 \ m/s^2} = 9.6 s$$The horizontal distance traveled by the projectile is:$$x = v_{x}t = (16.4 \ m/s)(9.6 s) = 164 m$$

A Projectile Is Launched from Ground Level at an Angle