The energy is obtained from the motion of toy car
Conclusion:
- Moving objects possess energy
- The energy possessed by a body by virtue of its motion is the Kinetic energy
Experiment:
Let’s do another activity. Allow a powder tin to slide down a polished, inclined plane as shown in the figure and let it hit a toy car. Try to measure the displacement of the toy car. Repeat the experiment by increasing the height of the inclined plane and filling the tin with sand.
Observation:
- The displacement of the toy car is greater When it is hit by the powder filled with sand
- Also the displacement is greater when it is dropped from a greater height
Conclusion: Kinetic energy depends on mass (m) and velocity (v)
Derivation of the equation for calculating K.E
Work W = Fs
As per II law of motion
F = ma
∴ W = mas
According to third equation of motion
v2 = u2 + 2as = 0 + 2as (u = 0) = 2as
∴ as = \(\frac{v^2}{2}\)
W = mas , if we put \(\frac{v^2}{2}\) instead of as
W = \(\frac{mv^2}{2}=\frac{1}{2}mv^2\)
W = \(\frac{1}{2}mv^2\)
Work is equal to the magnitude of kinetic energy
i.e, Kinetic energy K = \(\frac{1}{2}\) mv2
M – mass, V – Velocity
When a body of mass m moves with a velocity v, its kinetic energy will be K = \(\frac{1}{2}\) mv2
