Physics MCQs

Physics

Work and Energy


Page 13 of 23

#97

Dimensions of power are:

A) $M^{0}L^{0}T^{-1}$

B) $ML^{2}T^{-2}$

C) $MLT^{-2}$

D) $ML^{2}T^{-3}$

Answer:   D
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#98

For a conservative force, the potential energy function $U$ satisfies:

A) $\nabla\times\vec F=\nabla U$

B) $\vec F=+\nabla U$

C) $\vec F=-\nabla U$

D) $\nabla\cdot\vec F=U$

Answer:   C
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#99

At the bottom of a frictionless track, potential energy is minimum and kinetic energy is:

A) maximum

B) undefined

C) zero

D) minimum

Answer:   A
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#100

Dimensions of power are:

A) $M^{0}L^{0}T^{-1}$

B) $ML^{2}T^{-3}$

C) $MLT^{-2}$

D) $ML^{2}T^{-2}$

Answer:   B
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#101

At the bottom of a frictionless track, potential energy is minimum and kinetic energy is:

A) zero

B) maximum

C) undefined

D) minimum

Answer:   B
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#102

Instantaneous power delivered by a constant force is:

A) $P=F/v$

B) $P=\vec F\cdot\vec v$

C) $P=Fv\sin\theta$

D) $P=F^2v$

Answer:   B
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#103

A constant force $F=20\,\text{N}$ acts through $s=4\,\text{m}$ at $\theta=60^\circ$. The work done is:

A) $20s\,\cos60^\circ$

B) $F+s$

C) $F/s$

D) $Fs$

Answer:   A
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#104

The work–energy theorem for a particle of mass $m$ is:

A) $W_{\text{net}}=m\Delta v$

B) $W_{\text{net}}=\Delta K$

C) $W_{\text{net}}=\Delta U$

D) $W_{\text{net}}=\Delta p$

Answer:   B
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Page 13 of 23