Practice problems combining Newton's laws of motion with principles of energy conservation in physical systems.
Power P=W/t=F·v per NCERT. Rate of doing work. With given force and velocity, P=Fv. Calculation yields 180 W. Hence option B correctly represents power.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Initial K=12×800×122=57600J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 5 m. 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: Laws of Motion and Energy Conservation
Power P=W/t=F·v per NCERT. Rate of doing work. With given force and velocity, P=Fv. Calculation yields 160 W. Hence option B correctly represents power.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives -1.5 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives 495 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Kinetic energy K=½mv² and potential U=mgh per NCERT. Energy conservation K+U=constant for conservative forces. Substituting m, v, h gives 48169 as energy, matching option A.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
At top, vC=gL, energy conservation: 12mv02=12m(gL)+2mgL. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 12 m. 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: Laws of Motion and Energy Conservation
Kinetic energy K=½mv² and potential U=mgh per NCERT. Energy conservation K+U=constant for conservative forces. Substituting m, v, h gives 11.1% as energy, matching option A.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
For elastic collision, momentum and kinetic energy conserved: m1v1+m2v2=m1v1'+m2v2' and ½m1v1²+... per NCERT. Solving gives velocities matching 3 m/s. Inelastic loses energy. So option A is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives 40 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Kinetic energy K=½mv² and potential U=mgh per NCERT. Energy conservation K+U=constant for conservative forces. Substituting m, v, h gives 66 J as energy, matching option B.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
Initial Ki=12×8×22=16J. 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 B is scientifically correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Laws of Motion and Energy Conservation
