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Grade 11Mechanics

Find the relation between acceleration of blocks in figure. If acceleration of small block =a and mass=m, whereas account of big one=A and mass=M

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8 Years agoGrade 11
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ApprovedApproved Tutor Answer11 Months ago

To find the relationship between the accelerations of two blocks in a system, we need to consider the forces acting on each block and how they interact with one another. Let's assume we have a small block with mass \( m \) and acceleration \( a \), and a larger block with mass \( M \) and acceleration \( A \). The specific configuration of the blocks (e.g., whether they are stacked, connected by a pulley, or in contact) will influence the relationship between their accelerations. For simplicity, let’s consider a common scenario where the small block is resting on top of the larger block, which is on a frictionless surface.

Analyzing the System

In this setup, the small block experiences gravitational force downward and normal force from the larger block upward. The larger block, in turn, may be influenced by the force exerted by the small block. Here’s how we can break it down:

Forces on the Small Block

The forces acting on the small block can be described as follows:

  • Weight: \( W = mg \) (acting downward)
  • Normal Force: \( N \) (acting upward)

Since the small block is not accelerating vertically, the normal force equals the weight:

N = mg

Forces on the Large Block

Now, let’s consider the larger block. The force exerted by the small block on the larger block due to its weight is equal to the normal force:

F = N = mg

This force causes the larger block to accelerate. According to Newton's second law, the acceleration of the larger block can be expressed as:

F = Ma

Substituting the force from the small block:

mg = MA

Relating the Accelerations

Now we have two equations:

  • For the small block: \( a = A \) (since they move together horizontally)
  • For the larger block: \( mg = MA \)

From the second equation, we can express the acceleration of the larger block in terms of the mass of the small block and the mass of the larger block:

A = \frac{mg}{M}

Final Relationship

Since we established that \( a = A \), we can substitute \( A \) into the equation:

a = \frac{mg}{M}

This equation shows the relationship between the accelerations of the two blocks. The acceleration of the small block is directly proportional to its mass and inversely proportional to the mass of the larger block. This means that as the mass of the larger block increases, the acceleration of the small block decreases, assuming the mass of the small block remains constant.

Example Scenario

Let’s say the small block has a mass of 2 kg and the larger block has a mass of 4 kg. Plugging these values into our derived formula:

a = \frac{(2 \, \text{kg})(9.81 \, \text{m/s}^2)}{4 \, \text{kg}} = 4.905 \, \text{m/s}^2

This means that both blocks will accelerate at approximately 4.905 m/s² to the right, demonstrating how the masses influence the system's dynamics.

Understanding these relationships helps in analyzing more complex systems involving multiple blocks and forces, allowing for a deeper grasp of Newtonian mechanics.