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Classical Mechanics

Work

Concept Quizzes

Work Warmup
Work-kinetic energy theorem
Work done by a constant force
Rocket physics
Work-energy theorem (vector form)
Power input to a system
Work 1D - Problem Solving
Work 2D - Problem Solving

Challenge Quizzes

Work: Level 2 Challenges
Work: Level 3 Challenges

Work 1D - Problem Solving

A body of mass $m = 2 \text{ kg}$ is dropped from $h = 70 \text{ cm}$ above a horizontal platform that is fixed to one end of an elastic spring, as shown in the figure above. As a result the spring is compressed by an amount of $\Delta x = 20 \text{ cm}.$ What is the spring constant of the spring?

The gravitational acceleration is $g= 10 \text{ m/s}^2$ and the air resistance is negligible.

900 \text{ N/m}

450 \text{ N/m}

4 \text{ N/m}

9 \text{ N/m}

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by Brilliant Staff

A body initially at rest is dropped from a height of $h = 45\text{ m}.$ If the coefficient of restitution is $e= 0.6,$ what is the height the body reaches at the second bounce?

The gravitational acceleration is $g= 10 \text{ m/s}^2.$

5.832

\text{ m}

11.664

\text{ m}

16.2

\text{ m}

32.4

\text{ m}

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by Brilliant Staff

A $14$ -meter-long rod of mass $2 \text{ kg}$ with homogeneous density is standing vertically with one end on a horizontal floor. Find the gravitational potential energy of the rod.

The gravitational acceleration is $g = 10 \text{ m/s}^2.$

70 \text{ J}

280 \text{ J}

140 \text{ J}

210 \text{ J}

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by Brilliant Staff

A body of mass $m = 5 \text{ kg}$ is moving on a frictionless horizontal plane with a velocity of $v= 4 \text{ m/s}.$ The body is heading to the vertical platform fixed to one end of an elastic spring, as shown in figure above. As a result the spring is compressed by an amount of $\Delta x = 20 \text{ cm}.$ What is the spring constant of the spring?

40 \text{ N/m}

1000 \text{ N/m}

2000 \text{ N/m}

20 \text{ N/m}

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by Brilliant Staff

A block of mass $m_1 = 3 \text{ kg}$ is moving on a frictionless horizontal surface with a velocity of $u_1 = 16 \text{ m/s}$ towards another block of mass $m_2 = 9 \text{ kg}$ that is moving on the same surface with a velocity of $u_2 = 8 \text{ m/s}$ in the same direction. A massless spring of spring constant $k = 36 \text{ N/m}$ is attached to $m_2$ as shown in figure above. When block $m_1$ collides with the spring, what is the maximum change in the spring's length?

6 \text{ m}

8 \text{ m}

2 \text{ m}

4 \text{ m}

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by Brilliant Staff