Force and Motion Unit Test

Question

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Question
Two construction workers are attempting to pull a slab of concrete off of the ground. Each of the workers are pulling up with a force of 225 N, while the slab of concrete applies a gravitational force of 400 N in the opposite direction, remaining stationary.

If the pulling forces applied to the slab of concrete are assigned a positive value, what is the net force of the scenario, and in which direction will the slab of concrete move?

(1 point)
Responses

-50 N; the slab will remain stationary
-50 N; the slab will remain stationary

-175 N; the slab will remain stationary
-175 N; the slab will remain stationary

175 N; the slab will move upward
175 N; the slab will move upward

50 N; the slab will move upward
50 N; the slab will move upward
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Answer 1

To determine the net force in this scenario, we can follow these steps:

1. Identify the forces involved:

   • The two workers are each pulling with a force of 225 N: \[ 225 , \text{N} + 225 , \text{N} = 450 , \text{N} \text{ (upward)} \]
   • The gravitational force acting on the slab of concrete is 400 N (downward).

2. Calculate the net force: \[ \text{Net Force} = \text{Total Upward Force} - \text{Gravitational Force} \] \[ \text{Net Force} = 450 , \text{N} - 400 , \text{N} = 50 , \text{N} \text{ (upward)} \]

3. Direction of motion: Since the net force is positive (50 N) and directed upward, the slab of concrete will move upward.

Given these calculations, the correct response is:

50 N; the slab will move upward.