1.

A spring balance has a scale that reads from 0 to 50 kg. The length of the scale is 20 cm. A body suspended from this balance, when displaced and released, oscillates with a period of 0.6 s. What is the weight of the body ?

Answer»

Solution :Maximum displacement of the spring `trianglel = 20 cm = 0.2 m`
Time period `T = 0.6 s, g = 9.8 ms^(-2)`
Maximum force exerted on the spring `F= mg`
`= 50xx 9.8= 490N`
Now, force CONSTANT `k= (F)/(triangle l)`
`therefore k = (490)/(0.2)= 2450 Nm^(-1)`
But time period `T= 2pi SQRT((m)/(k))`
`therefore (T^(2)k)/(4PI^(2))= m`
`therefore ((0.6)^(2)xx2450)/(4xx(3.14)^(2))=m`
`therefore m= 22.36 kg`.
Weight of the body = mg
`22.36xx 9.8 = 219.1N = 22.36 kgf`.


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