Final answer:
The initial upward velocity of an object thrown straight up is a positive value, determined by the force of the throw and required to overcome gravity, which provides a constant negative acceleration. In the absence of air resistance, any projectile with a specific initial vertical component of velocity would reach a predictable maximum height, like the example of 67.6 m/s reaching 233 m. Therefore, the correct answer is d) None of the above.
Step-by-step explanation:
When an object is thrown straight up, it has an initial upward velocity, which is the speed at which the object is moving upward at the moment it leaves the thrower's hand. According to the given information, discussing the case where up is positive, the initial velocity will also be positive.
However, as gravity always acts downwards, the acceleration due to gravity (a = g = -9.80 m/s²) is negative. Computers and technology are thus employed to predict such situations.
For example, a projectile with a 67.6 m/s initial vertical component of velocity will reach a maximum height of 233 m, neglecting air resistance. This concept is particularly applicable in physics problems that involve one-dimensional motion, such as throwing an object straight up and having it fall back down to Earth.
During such motion, the object's velocity will be zero at its maximum height, and the direction of the velocity will change as it starts to fall back down. However, the acceleration (due to gravity) remains constant in magnitude and direction throughout the ascent and descent. In practice, air resistance affects the projectile, so the velocity required to reach the same height would have to be slightly higher.