A wooden block is floating in water contained in a beaker. If the beaker is placed in a freely falling elevator, during the free fall, the up thrust on the block will be

Options

A. Equal to the weight of the block
B. Slightly more than the weight of the block
C. Slightly less than the weight of the block
D. Zero.

Explanation

To solve the problem, we need to analyze the situation of the wooden block floating in water inside a beaker that is placed in a freely falling elevator. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Concept of Upthrust
Upthrust (or buoyant force) is the upward force exerted by a fluid on an object that is submerged or floating in it. It is equal to the weight of the fluid displaced by the object.

### Step 2: Identify the Conditions of the Problem
In this scenario, we have:
- A wooden block floating in water.
- The entire system (beaker with water and block) is in a freely falling elevator.

### Step 3: Analyze the Effects of Free Fall
When an object is in free fall, it experiences a condition where the effects of gravity are not felt in the same way as when it is at rest or moving with constant velocity. This is because both the object and the fluid (water) are falling together at the same acceleration due to gravity.

### Step 4: Determine the Apparent Weight
During free fall, the apparent weight of the wooden block becomes zero. This means that the block does not exert any force on the water below it, and therefore, the water does not exert any upward force (upthrust) on the block.

### Step 5: Conclude the Upthrust
Since the apparent weight of the wooden block is zero during free fall, the upthrust acting on the block also becomes zero.

Thus, the upthrust on the block will be **zero**.

### Final Answer
The upthrust on the block will be **zero**.

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