Talon Mcbride
2022-07-16
Answered

A force F directed upwards is applied on an object resting on a flat surface. The object then moved to the right. Which of the following is TRUE about the upward force?a. F does work on the objectb. F is a conservative force c. F is gravitational forced. F caused the displacement of the objecte. Only the 1st and 3rd optionsf. Only the 2nd and 4th optionsg. None of the above

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sweetwisdomgw

Answered 2022-07-17
Author has **20** answers

Work done by a force is given as

$W=\overrightarrow{F}\cdot \overrightarrow{S}\phantom{\rule{0ex}{0ex}}W=FS\mathrm{cos}\theta \phantom{\rule{0ex}{0ex}}\text{Where}\theta \text{is the angle between force vector and displacement vector.}\phantom{\rule{0ex}{0ex}}\text{If}\theta ={90}^{\circ}\Rightarrow W=0$

Given that force F is acting in upward direction so it can not be a gravitational force because gravitational force is always attractive in nature. So, the direction gravitation force must be towards the center of the earth. So, F is not a gravitational force. Hence, option (C) is incorrect.

The force, F is acting in upward direction while the displacement of the object is in right. So, the angle between the force and displacement vector is right angle. So, the work done by the force, F is zero. Hence , option(A) is wrong.

As the work done by the force F is zero so the displacement of the object is not caused by the force, F. Therefore, option (D) can also be eliminated.

Now, force (F) is balancing the gravitational force which is a conservative force because the gravitational field is a conservative field. Therefore, force (F) is a conservative force.

Hence, the option (B) is the correct answer.

$W=\overrightarrow{F}\cdot \overrightarrow{S}\phantom{\rule{0ex}{0ex}}W=FS\mathrm{cos}\theta \phantom{\rule{0ex}{0ex}}\text{Where}\theta \text{is the angle between force vector and displacement vector.}\phantom{\rule{0ex}{0ex}}\text{If}\theta ={90}^{\circ}\Rightarrow W=0$

Given that force F is acting in upward direction so it can not be a gravitational force because gravitational force is always attractive in nature. So, the direction gravitation force must be towards the center of the earth. So, F is not a gravitational force. Hence, option (C) is incorrect.

The force, F is acting in upward direction while the displacement of the object is in right. So, the angle between the force and displacement vector is right angle. So, the work done by the force, F is zero. Hence , option(A) is wrong.

As the work done by the force F is zero so the displacement of the object is not caused by the force, F. Therefore, option (D) can also be eliminated.

Now, force (F) is balancing the gravitational force which is a conservative force because the gravitational field is a conservative field. Therefore, force (F) is a conservative force.

Hence, the option (B) is the correct answer.

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