define energy,give the definition for knietic energy for an object and derive an expression for energy possessed by a moving object.Can knietic energy of a body be negative?
Answers
Answer:
Energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. There are, moreover, heat and work—i.e., energy in the process of transfer from one body to another.
Answer:
ANSWER
Kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
Derivation:
Let us consider an object of m which is at rest lying on a table.
Let A force F acts on the object which moves the object through a distance S.
The workdone=F×S
W=F
net
×S-------(1)
Let the work done on the object causes a change in its velocity from u to V and let a be the acceleration.
From Third equation of motion:
V²−u²=2as
s=V²−u²/2a----------(2)
By Newton's Second law:
F=ma------(3)
From equation (1), (2) and (3)
W=ma×(V
2
−u
2
/2a)=(1/2)m(V
2
−u
2
)
As we assumed object at rest, u=0
W=(1/2)mV
2
we know that the kinetic energy of a body moving with a certain velocity is equal to work done on the object to acquire that velocity from rest.
∴K.E=1/2mV
2