Tag: physics

Questions Related to physics

Will it make any difference in the extension of the spring, if 3 springs of spring constant k are joined in series to life a load W as compared to one string of spring constant k to lift the same load

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. Extension in long spring < extension in shorter spring

  2. Extension in long spring > extension in shorter spring

  3. Extension in both the springs are same

  4. None of the above

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Correct Option: A
Explanation:

If three springs are joined together, their effective spring constant will be k/3. Since load is W, we can write $W=(k/3)x _1$.

If these strings are replaced by a long spring of spring constant k, let the extension of the load be W, we can still write $W=kx _2$

Comparing these two equations, we get, $x _2=x _1/3$ or the extension in the long spring is less than the shorter springs

How many identical springs of spring constant k should be joined in series, so the effective spring constant is k/2

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. 8

  2. 4

  3. 1

  4. 2

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Correct Option: D
Explanation:

effective spring constant will be $K _{eff}=(k)(k)/(k+k)=k/2$

The correct answer is option(d)

If two springs of spring constants $k _1$ and $k _2$ whose extensions upon applying a force F are $x _1$ and $x _2$ respectively are joined together in a series configuration, the net extension will be 

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. $x= F(1/k _1+1/k _2)$

  2. $x= F(1/k _1-1/k _2)$

  3. $x= F(k _1+k _2)$

  4. $x= F(k _1-k _2)$

Show answer
Correct Option: A
Explanation:

$x _1 = F/k _1$ and $x _2=F/k _2$

Upon joining both the springs together, the net extension will be $x =x _1+x _2$

Substituting, we get, $x= F(1/k _1+1/k _2)$

The correct option is (a)


A spring of force constant k is cut into 4 equal parts. The spring constant of each piece become_______ times and time period will become______ times.

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. [5, 1/2]

  2. [4, 1/2]

  3. [7, 1/2]

  4. [4, 1/3]

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Correct Option: B

When two blocks connected by a spring move towards each other under mutual interaction:

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. Their velocities are equal and opposite

  2. Their accelerations are equal and opposite

  3. The forces acting on them are equal and opposite

  4. Their momenta are equal and opposite.

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Correct Option: C
Explanation:

If we take the two blocks plus spring as the system there is no external force acting on this system.
The accelerations will be equal and opposite if masses are equal. Since the forces are internal, they will be equal and opposite.

Two springs have their force constants ${ K } _ { 1 }$ and ${ K } _ { 2 }.$ Both are stretched till their elastic energies are equal. Then,ratio of stretching forces ${ K } _ { 1 } / { K } _ { 2 }$ is equal to:

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. $K _ { 1 } / K _ { 2 }$

  2. $\mathbf { K } _ { 2 } : \mathbf { K } _ { 1 }$

  3. $\sqrt { K _ { 1 } } : \sqrt { K _ { 2 } }$

  4. $\mathbf { K } _ { 2 } ^ { 2 } : \mathbf { K } _ { 2 } ^ { 2 }$

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Correct Option: C

A mass of 2 kg falls from a height of 40 cm, on a spring with a force constant of 1960 N/m. The spring is compressed by ? (Take $g=9.8m/s^2$)

physics simple harmonic motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. 9 cm

  2. 1.0 cm

  3. 20 cm

  4. 5 cm

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Correct Option: A

A string fixed at both ends vibrates in a resonant mode with separation of $6.0$cm between the consecutive nodes. For the next to next higher resonant frequency this separation is reduced by $2.0$cm. The length of the spring is 

physics simple harmonic motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. 8 cm

  2. 16 cm

  3. 24 cm

  4. 32 cm

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Correct Option: A

One end of a light spring of force constant K is fixed to ceiling the other end is fixed to block of mass M initially the spring is relaxed the work done by the external agent to lower the Hanging body of mass M slowly till it comes to equilibrium is

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. $3 m^2 g^2/ 2k$

  2. $m^2 g^2/ 2k$

  3. $-3 m^2 g^2/ 2k$

  4. $- m^2 g^2/ 2k$

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Correct Option: A

A spring oscillates with frequency $1$ cycle per second. What approximate length must a simple pendulum have to oscillate with that same frequency?

physics oscillatory motion motion of a mass suspended by two springs example of simple harmonic motion oscillations due to a spring

  1. 25 cm

  2. 50 cm

  3. 67 cm

  4. 90 cm

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Correct Option: B