To sketch a velocity-time graph for a body thrown vertically upwards, you'll follow these steps:
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Initial Velocity (Upwards): At the moment of release, the body has an initial positive velocity, which is the speed at which it is thrown upwards. This is represented as a point above the time (x-axis) at the origin.
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Deceleration Due to Gravity: As the body moves upwards, it will experience a constant negative acceleration due to gravity (approximately -9.81 m/s²). This will cause the velocity to decrease linearly over time until it reaches zero at the maximum height.
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Maximum Height: At the peak of its trajectory, the velocity will be zero (the highest point reached). This is the point where the graph touches the x-axis.
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Descent: After reaching the maximum height, the body will begin to fall back down, and its velocity will become negative. The velocity will increase in magnitude (going further negative) as it falls, also depicted as a straight line downwards.
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Final Graph: The graph starts at a positive value (initial upward velocity), slopes downwards to zero (at max height), and then continues downward into the negative region, indicating downward velocity as the body falls back down.
Sketch Description:
- The x-axis represents time.
- The y-axis represents velocity.
- Start the graph above the x-axis at the initial velocity.
- Draw a straight line downwards to the x-axis (maximum height at zero velocity).
- Continue the line downwards into the negative area, indicating increasing negative velocity as the object falls.
The graph will look like this in a simple representation:
Velocity
|
| *
| \
| \
|__________*__________ Time
(maximum height)
In this sketch:
- The asterisk (*) represents the maximum height where the velocity is zero.
- The slope downwards represents the decreasing velocity as the object rises.
- The continuation downwards into the negative represents the increasing downward velocity as the object falls.
This graph conveys the complete motion of the body thrown vertically upwards!