Which of the following statements are true of the horizontal motion of projectil
ID: 1355588 • Letter: W
Question
Which of the following statements are true of the horizontal motion of projectiles? True or False?
A. A projectile with a rightward component of motion will have a rightward component of acceleration.
B. The horizontal velocity of a projectile changes by 9.8 m/s each second.
C. A projectile with a horizontal component of motion will have a constant
horizontal velocity.
D. The horizontal velocity of a projectile is 0 m/s at the peak of its trajectory.
E. The horizontal velocity of a projectile is unaffected by the vertical velocity; these
two components of motion are independent of each other.
F. The horizontal displacement of a projectile is dependent upon the time of flight
and the initial horizontal velocity.
G. The peak height reached by a projectile depends upon its horizontal velocity.
H. Considering a projectile launched from ground level at a fixed launch angle and
landing at ground level: the horizontal displacement (i.e., the range) of the projectile will always increase as the launch speed is increased.
Explanation / Answer
A ) FALSE : A projectile with a rightward motion (in addition to a vertical motion) will have a constant velocity in the rightward direction. This is to say that it has no horizontal acceleration.
B ) FALSE - A projectile has a constant horizontal velocity. The vertical velocity will change by 9.8 m/s each second.
C ) TRUE - Absolutely true! Projectiles are objects being acted upon by gravity alone. As such, there is a vertical acceleration but no horizontal acceleration. The horizontal velocity of a projectile is either zero or a constant nonzero value.
D ) FALSE - The vertical velocity of a projectile is 0 m/s at the peak of its trajectory; but the horizontal component of the velocity at the peak is whatever the value was when first launched.
E ) TRUE - For any two dimensional motion, perpendicular components of the motion are independent of each other. Any alteration in a vertical component will not effect the horizontal components of motion.
F ) TRUE - The horizontal displacement (x) can be calculated with the formula x = vox • t, where vox is the initial horizontal velocity and t is the time. These are the two variables which effect the horizontal displacement of a projectile.
G ) False - At peak height vertical velocty is zero , horizontal velocity throughout remain cosntant
H ) TRUE - As the launch speed is increased, the components of the initial velocity (both the horizontal and the vertical) increase as well. This causes the projectile to stay in the air for a longer period of time and to be moving faster in the horizontal direction. The result is that increased launch speeds always lead to increased horizontal displacements.