Final answer:
The statement that the unsupported time depends on height is False because the time of flight for an object thrown into the air depends on its initial velocity. Other misconceptions about physics such as force required to move an object on a ramp, skydiver's weightlessness, and balance on the moon, were also clarified as false.
Step-by-step explanation:
The correct answer to the student's question is False. The time a body remains unsupported when projected upwards does depend on the height to which it is projected. According to the laws of motion and gravity, the higher an object is projected, the longer it will stay in the air before returning to the ground. For an object thrown vertically upward, its time of flight depends on its initial velocity; the higher the initial velocity, the higher it will rise and the longer it will stay in the air. However, the acceleration due to gravity will eventually bring the object down regardless of the height it reached.
Considering the additional information provided, here's a clarification of those statements:
- 45. False - The force required to push the box up the ramp depends on several factors, including the box's weight, the ramp's angle (not just its height), and the coefficients of static and kinetic friction between the box and the ramp.
- 60. False - A skydiver reaching terminal velocity is not weightless. Terminal velocity occurs when the force of gravity is balanced by air resistance, resulting in no further acceleration.
- 17. False - The balance is still level, but because the moon's gravitational acceleration is approximately 1/6th of Earth's, both the book and the iron weight would weigh less, although they would still balance each other.