You can't get a negative number by multiplying positive numbers. Your equation represents force and displacement in the same direction. The force is positive and the displacement is positive.Ineedhelpwithphysics said:Homework Statement: A pump is required to lift 850 kg
of water per minute from a well 14.7 m
deep and eject it with a speed of 17.7 m/s
Relevant Equations: W = F*d
W = delta KE
Im confused I did
850*9.8*14.7 = 1.2x10^5
Why is it not negative since the force is opposite to the motion?
A positive sign of work indicates that the force applied to an object is in the same direction as the object's displacement. This means that energy is being transferred to the object, causing it to move or accelerate in the direction of the force.
A negative sign of work indicates that the force applied to an object is in the opposite direction to the object's displacement. This means that energy is being taken away from the object, often causing it to slow down or decelerate.
The sign of work is determined by the angle between the force vector and the displacement vector. If the angle is less than 90 degrees, the work is positive. If the angle is greater than 90 degrees, the work is negative. If the angle is exactly 90 degrees, no work is done.
Yes, the sign of work can be zero. This occurs when the force applied is perpendicular to the direction of displacement, meaning no work is done. An example of this is when an object moves in a circular path under a centripetal force; the force is perpendicular to the displacement, resulting in zero work.
The concept of the sign of work is important because it helps in understanding how energy is transferred within a system. Positive work indicates energy input, while negative work indicates energy removal. This understanding is crucial for analyzing and predicting the behavior of physical systems in various applications, from simple mechanics to complex thermodynamics.