Problems and solutions centered on the work-energy theorem, showing how work done relates to changes in kinetic energy.
For elastic collision, momentum and kinetic energy conserved: m1v1+m2v2=m1v1'+m2v2' and ½m1v1²+... per NCERT. Solving gives velocities matching 0 m/s. Inelastic loses energy. So option A is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives -3.4 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Potential energy V=mgh=1.5×10×16=240J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 17 m/s. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Work W=20×6=120J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 7 m/s. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
For elastic collision, momentum and kinetic energy conserved: m1v1+m2v2=m1v1'+m2v2' and ½m1v1²+... per NCERT. Solving gives velocities matching 9 m/s. Inelastic loses energy. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Power P=W/t=F·v per NCERT. Rate of doing work. With given force and velocity, P=Fv. Calculation yields 225 W. Hence option B correctly represents power.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Kinetic energy K=½mv² and potential U=mgh per NCERT. Energy conservation K+U=constant for conservative forces. Substituting m, v, h gives 80 J as energy, matching option B.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Kinetic energy K=½mv² and potential U=mgh per NCERT. Energy conservation K+U=constant for conservative forces. Substituting m, v, h gives 200 m/s as energy, matching option B.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Potential energy mgh=4×10×3=120J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 7 m/s. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Work W=45×7=315J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 8 m/s. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
Potential energy V=mgh=0.2×10×12=24J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 14 m/s. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
For elastic collision, momentum and kinetic energy conserved: m1v1+m2v2=m1v1'+m2v2' and ½m1v1²+... per NCERT. Solving gives velocities matching 4 m/s. Inelastic loses energy. So option A is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Work, Energy and Power - Work-Energy Theorem
