A spring hangs from the ceiling with an unstretched length of x 0 = 0.69 m x0=0.69 m . A m 1 = 7.5 kg m1=7.5 kg block is hung from the spring, causing the spring to stretch to a length x 1 = 0.84 m x1=0.84 m . Find the length x 2 x2 of the spring when a m 2 = 2.1 kg m2=2.1 kg block is hung from the spring. For both cases, all vibrations of the spring are allowed to settle down before any measurements are made.

x2=0.732m

Explanation:

We can calculate the spring constant using the equilibrium equation of the block m1. Since the spring is in equilibrium, we can say that the acceleration of the block is equal to zero. So, its equilibrium equation is:

Then using the equilibrium equation of the block m2, we have:

In words, the lenght x2 of the spring when the m2 block is hung from it, is 0.732m.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.