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A spring balance has a scale that reads from 0 to 70 kg. The length of the scale is 0.20 cm. A body suspended from this balance. when displaced and released oscillates with a Period of 0.9 sec. What is the weight of the body?

Option: 1

75 N


Option: 2

69  N


Option: 3

89 N


Option: 4

20 N


Answers (1)

best_answer

Length of Scale = 0.20 cm = 0.0020 m

Total scale reading = 70 kg

\therefore F=M g=70 \times 9.8=686 \mathrm{~N} \\

x=0.20 \mathrm{~cm}=0.0020 \mathrm\,{M}

\therefore Force \,\,\,constant, k=\frac{F}{x}=\frac{686}{0.0020}

=343000 \mathrm{~N} / \mathrm{m}

Now \,\,\,\,\,\,T=2 \pi \sqrt{\frac{M}{K}}

\therefore M=\frac{T^2 K}{4 \pi^2}=\frac{(0.9)^2 \times 343000}{4 \times(3.14)^2} \\

=\frac{0.81 \times 343000}{4 \times 9.8596}=\frac{81 \times 343000 \times 10000}{4 \times 98596 \times 100} \\

=\frac{8100 \times 343000}{4 \times 98596}=\frac{2778300000}{394384} \\

=7044.66 \mathrm{~kg}

Hence, weight of body = Mg

=7044.66 \times 9.8=69037.67 \mathrm{~N}

Posted by

shivangi.shekhar

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