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Grade 12th passMechanics

Can you pls derive velocity in case of vertical motion for rod!??

Profile image of Richa jain
7 Years agoGrade 12th pass
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1 Answer

Profile image of Askiitians Tutor Team
ApprovedApproved Tutor Answer1 Year ago

To derive the velocity for a rod in vertical motion, we first need to understand the basic principles of motion under the influence of gravity. When a rod is dropped or thrown vertically, its motion can be described using the equations of kinematics. Let's break this down step by step.

Understanding Vertical Motion

Vertical motion is primarily influenced by gravitational acceleration, which is approximately 9.81 m/s² downward. This means that any object in free fall will accelerate towards the Earth at this rate, assuming air resistance is negligible.

Key Variables

Before we derive the velocity, let’s define some key variables:

  • u: Initial velocity of the rod (m/s)
  • g: Acceleration due to gravity (approximately 9.81 m/s²)
  • t: Time in seconds (s)
  • v: Final velocity of the rod (m/s)

Deriving the Velocity Equation

The equation that relates these variables in vertical motion is derived from the basic kinematic equation:

v = u + gt

Here’s how this equation works:

  • If the rod is dropped from rest, the initial velocity (u) is 0. Thus, the equation simplifies to v = gt.
  • If the rod is thrown downward with an initial velocity, you simply add that initial velocity to the product of gravitational acceleration and time.

Example Calculation

Let’s say we drop a rod from a height with no initial velocity (u = 0). After 2 seconds, we want to find its velocity:

  • Using the formula: v = gt
  • Substituting the values: v = 9.81 m/s² * 2 s = 19.62 m/s

This means that after 2 seconds, the rod will be moving downward at a velocity of 19.62 m/s.

Considering Different Scenarios

If the rod is thrown upward with an initial velocity, the motion becomes a bit more complex. The rod will first decelerate until it reaches its peak height, where the velocity becomes zero, and then it will start falling back down. The velocity at any point during this motion can still be calculated using the same kinematic equation, adjusting the initial velocity accordingly.

Final Thoughts

In summary, the velocity of a rod in vertical motion can be derived using the basic principles of kinematics, taking into account the initial velocity and the effect of gravity. This understanding is crucial for solving various physics problems related to motion. Whether the rod is dropped or thrown, the same principles apply, allowing us to predict its behavior accurately.