If 27 j of work are needed to stretch a spring from 15 cm to 21 cm and 45 j are needed to stretch it from 21 cm to 27 cm, what is the natural length of the spring?

9 cm.

Explanation:

The energy used for stretch the spring from to will be ,

The energy used for stretch the spring from to will be ,

using the energy of spring formula ,we find that

Dividing both the equation will get,

Therefore, the natural length of the spring is, 9 cm.

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles