Students can go through AP Inter 1st Year Physics Notes 6th Lesson Work, Energy and Power will help students in revising the entire concepts quickly.
AP Inter 1st Year Physics Notes 6th Lesson Work, Energy and Power
→ The scalar product (or) dot product of any two vectors A and B denoted as A.B = AB cos θ.
→ The dot product of A and B is a scalar.
→ Dot product obey’s commutative law. \(\vec{A} \cdot \vec{B}=\vec{B} \cdot \vec{A}\)
→ Dot product obeys distributive law \(\vec{A} \cdot(\vec{B}+\vec{C})=\vec{A} \cdot \vec{B}+\vec{A} \cdot \vec{C}\)
→ The work done is a scalar quantity. It can be positive (or) negative.
→ Work done by the friction (or) viscous force on a moving body is negative.
→ The work – energy theorem states that the change in K.E of a body is the work done by the net force on the body.
Kf – Ki = WNet
→ The work-energy theorem is not independent of Newtons second law.
→ The work-energy theorem holds in all internal forces.
→ The P.E of a body subjected to a conservative force is always undetermined upto a constant.
→ Work done by friction over a closed path is not zero and no potential energy can be associated with friction.
→ The energy possessed by a body by virtue of its position (or) state is called potential energy. V(h) = mgh, if h is taken as variable.
→ The energy possessed by a body by virtue of its motion is called kinetic energy
K = \(\frac{1}{2}\)mv2.
→ Work done by a variable force W = \(\int_{x_1}^{x_1} F(x)\)
→ The total mechanical energy of a system observed if the forces, doing work on it, are conservative.
→ The spring force is a conservative force.
→ Eiitstein mass-energy relation is E = mC2
Where C = 3 × 108 m/s = Velocity of light
→ The rate of doing work is called power, Pav = \(\frac{W}{t}\)
→ Another unit of power is horse – power (HP) 1 H.P = 746 W.
→ Collision is an interaction between two (or) more bodies in which sudden changes of momenta take place.
→ In an elastic collision both K.E. and linear momentum are conserved.
→ A collision in which only momentum.is conserved but not the K.E is called inelastic collision.
→ Coefficient of restitution (e) = \(=\frac{\text { Relative velocity of separation }}{\text { Relative velocity of approach }}\)