A string is stretched by 2cm and its potential energy is u .if it is strechted by 10 cm,the potential energy is:
A.u\5
B.5u
C.10u
D.25u
To answer this question, we need to understand the relationship between the stretch of the string and its potential energy.
The potential energy of a stretched string is directly proportional to the square of the stretch. In other words, if we double the stretch, the potential energy will increase by a factor of four (2^2) and so on.
In the given scenario, the string is stretched by 2cm, and its potential energy is given as u. Let's calculate the potential energy when the stretch is increased to 10cm.
First, we need to determine the ratio of the new stretch to the original stretch:
Ratio = New stretch / Original stretch = 10 cm / 2 cm = 5.
Now, based on the relationship mentioned earlier, the potential energy is proportional to the square of the stretch. Since the ratio of the new stretch to the original stretch is 5, the potential energy will increase by a factor of 5^2, which is 25.
Therefore, the potential energy when the string is stretched by 10cm is 25u.
So, the correct option is D. 25u.