Question map
A ball is thrown vertically in vacuum. It goes up and falls down on Earth. Which of the given figures represents its true time velocity graph?
Explanation
When a ball is thrown vertically upward in a vacuum, it is subject only to the constant acceleration due to gravity (g). According to the equation of motion v(t) = v0 - gt, the velocity-time graph must be a straight line with a constant negative slope [t1][t3]. Initially, the ball has a maximum positive velocity (upward). As it rises, it slows down until the velocity reaches zero at the highest point [c3][t5]. Subsequently, the ball falls downward, and its velocity becomes increasingly negative as it speeds up in the downward direction [t1][t4]. This motion is represented by a single continuous straight line that starts in the positive velocity region, crosses the time axis (v=0), and continues into the negative velocity region [t1][t5]. Figure II correctly depicts this linear relationship with a constant negative slope, reflecting uniform acceleration throughout the flight.
Sources
- [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.8: Let us observe > p. 72