Question #40

Practice Question

A.5 m/s
B.10 m/s
C.20 m/s
D.100 m/s

Concept Applied

Using conservation of mechanical energy: loss in potential energy = gain in kinetic energy. So, $mgh = \frac{1}{2}mv^2$. Solving, $v = \sqrt{2gh} = \s...

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Question #41

Practice Question

Concept Applied

Center of mass velocity remains unchanged in absence of external forces....

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Question #42

Practice Question

Concept Applied

Work = mgh = 5000 J, Power = 5000/10 = 500 W....

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Question #43

Practice Question

Concept Applied

First compute the acceleration $a=F/m=4\,\text{m/s}^{2}$. Using $s=\frac{1}{2}at^{2}$, the time to travel 3 m is $t=\sqrt{2s/a}=\sqrt{1.5}\approx1.225...

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Question #44

Practice Question

Concept Applied

By conservation: $mgh = \frac{1}{2}mv^2$ → $v = \sqrt{2gh} = \sqrt{100} = 10\,\text{m/s}$ (g=10)....

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Question #45

Practice Question

A.Theoretical foundations
B.Practical applications
C.Experimental data
D.Historical context

Concept Applied

Foundational check for Work, Energy and Power. Study the core principles carefully for competitive exams....

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Question #46

Practice Question

A.10 W
B.15 W
C.20 W
D.25 W

Concept Applied

Average power \(P_{avg}=\Delta K/\Delta t\). The kinetic energy increase \(\Delta K = 80 J‑20 J = 60 J\). Over 4 s, \(P_{avg}=60/4 = 15 W\)....

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Question #47

Practice Question

Concept Applied

Use $P = \frac{dW}{dt}$, integrate to find work, apply work-energy theorem....

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Question #48

Practice Question

A.\(\frac{u}{3}\)
B.\(\frac{2u}{3}\)
C.\(\frac{u}{2}\)
D.0

Concept Applied

For a one‑dimensional elastic collision, \(v_{1}=\frac{m_{1}-m_{2}}{m_{1}+m_{2}}\,u_{1}\). Substituting \(m_{1}=m\) and \(m_{2}=2m\) gives \(v_{1}=\fr...

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Question #49

Practice Question

A.-400 J
B.400 J
C.-200 J
D.200 J

Concept Applied

Work done by gravity is negative as force opposes displacement....

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Question #50

Practice Question

Concept Applied

Elastic collision implies $e = 1$, relative speed after = relative speed before....

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