If a body possesses constant kinetic energy, will there be work?
As work can only be done if there's a change in kinetic energy.
Work=∆KE
Answers
Answer:
If the object is traveling at a constant speed or zero acceleration, the total work done should be zero and match the change in kinetic energy. If the total work is positive, the object must have speed up or increased kinetic energy.
Common mistakes and misconceptions. Kinetic energy can't be negative, although the change in kinetic energy Δ K \Delta K ΔK can be negative. Because mass can't be negative and the square of speed gives a non-negative number, kinetic energy can't be
Answer:
The concept of work-energy theorem is often misunderstood. I'll try to explain it.
Firstly, let us understand what work in physics exactly means. Work is the displacement caused by an applied force on a body. In vector representation, W=F.S, which means that work(a scalar) equals the dot product of force (a vector) and displacement (also a vector). Work is actually a quantity that is analogous to energy. Work can be, informally speaking, thought of as a form of energy, according to the first law of thermodynamics. Thus, it can be added to or subtracted from a body's energy value.
According to the work-energy theorem, the work done on a body is equal to the total change in its mechanical energy.
If the body is acted upon by non-conservative forces, we can say that the work done on it is equal to the change in its kinetic energy. If the body is in a conservative force field, then the change in potential energy as well as kinetic energy is equal to the work done by all external and non-conservative forces. Here it is important to note that work done by conservative forces is defined as potential energy , but with a negative sign. The reason is that if we consider:
Change in KE= Work by conservative forces+ Work by non-conservative forces+Work by external forces
Or,
Change in KE-Work by conservative forces= Work by non-conservative forces+Work by external forces
Or,
Change in KE+ Change in PE=Work by non-conservative forces+Work by external forces