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STD 11 - 5. work,energy,power and collision — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 11 - 5. work,energy,power and collision4 Marks
MCQ
As shown in figure, two blocks are connected with a light spring. When spring was at its natural length, velocities are given to them as shown in figure. Choose the wrong alternative.
  • A
    Velocity of center of mass of the system is $3\, m/s$ (towards right)
  • B
    When spring is maximum compressed velocity of $20\, kg$ block is $3\, m/s$ (towards
    right)
  • C
    When spring is maximum elongated velocity of $10\, kg$ block is $3\, m/s$ (towards
    left)
  • ✓
    Both $(A)$ and $(C)$
✓

Answer

Correct option: D.
Both $(A)$ and $(C)$
d
$\mathrm{v}_{\mathrm{cm}}=\frac{20 \times 6-10 \times 3}{20+10}=3 \mathrm{m} / \mathrm{s}$ towards right.

At the time of either maximum elongation or compression, both the blocks will be moving with a common velocity $=3 \mathrm{m} / \mathrm{s}$ towards right.

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