in which of the following situation is mechanical work done?a, a girl chewing a piece of chewing gum .b,an acrobat supporting two men on his shoulders. c,a man standing with heavy loads on his head. d,a man try to lifts a heavy load bus with out any success. e,a body thrown vertically upwards to it's initial position
work done implies both a force and a distance that the object moves in the direction of the force.
if you squish gum, there is force and motion in direction of force so yes,work
no matter how many men you support on your shoulders if you do not move them up and down, no work.
to throw something up, force and distance.
Nice response
The situation where mechanical work is done is option D, where a man tries to lift a heavy load bus without any success. In this situation, the force is exerted on the bus to lift it, but no work is accomplished as the bus does not move.
In order to determine in which of the given situations mechanical work is done, we need to understand the concept of mechanical work and its defining factors.
Mechanical work is done when a force is applied to an object, causing it to move in the direction of the force. The formula for calculating mechanical work is given by:
Work = Force × Distance × cosθ
where:
- Force is the magnitude of the force applied on the object
- Distance is the distance over which the force is applied
- θ (theta) is the angle between the force vector and the displacement vector.
Let's analyze each of the given situations:
a) A girl chewing a piece of chewing gum: In this case, although there is a movement of the girl's jaw, it does not involve an external force acting on an object. Therefore, no mechanical work is done.
b) An acrobat supporting two men on his shoulders: In this situation, the acrobat is exerting a force to hold the two men on his shoulders against the gravitational force pulling them down. As the acrobat applies a force over a distance, mechanical work is done.
c) A man standing with heavy loads on his head: In this scenario, the man is not exerting any force to move an object. He is simply static, so no mechanical work is done.
d) A man trying to lift a heavy load bus without any success: In this case, while the man is applying a force to lift the bus, there is no displacement since the bus does not move. As displacement is zero, mechanical work is not done.
e) A body thrown vertically upwards to its initial position: When an object is thrown vertically upwards, it experiences the force of gravity acting against its motion. The force and the displacement vectors are in opposite directions. However, since the distance is positive and the angle between the force and displacement vectors is 180 degrees (cos 180° = -1), mechanical work is done.
So, the situations in which mechanical work is done are:
- An acrobat supporting two men on his shoulders.
- A body thrown vertically upwards to its initial position.
It is important to note that even though work is done in these situations, there might be other forms of work as well, such as thermodynamic work, electrical work, etc. Mechanical work specifically refers to the situation where a force is causing a displacement in an object.