IB Physics HL A.3.7 Mechanical Energy Conservation Question Bank

Practise HL mechanical-energy conservation with rolling bodies, rockets, springs and supplied rotational data in quantitative exam questions.

Exam points

Calculate speed for rolling bodies by combining translational, rotational and gravitational energy.
Use mechanical energy to explain changing rocket speed or calculate motion from height and energy stores.
Apply energy conservation with moments of inertia or elastic data, checking units and significant figures.

[Maximum number: 2]

An elastic climbing rope is tested by fixing one end of the rope to the top of a crane. The other end of the rope is connected to a block which is initially at position A. The block is released from rest. The mass of the rope is negligible.

diagram not to scale

The unextended length of the rope is 60.0 m . From position A to position B, the block falls freely.

At position B the rope starts to extend. Calculate the speed of the block at position B.

use of conservation of energy

OR
$\begin{aligned} & v^{2}=u^{2}+2 \operatorname{as} & v=\ll \sqrt{2 \times 60.0 \times 9.81}>=34.3<\mathrm{ms}^{-1}> \end{aligned}$

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A.3.7—Mechanical energy conservation question 1