Aluminum rod#1 has a length l and a diameter d. aluminum rod#2 has a length 2l and a diameter 2d. if rod#1 is under tension t and rod#2 is under tension 2t, how do the changes in length of the two rods compare?
a) rod #2 has quadruple the change in length that rod #1 has.
b) rod #2 has double the change in length that rod #1 has.
c) rod #1 has double the change in length that rod #2 has.
d) they are the same.
e) rod #1 has quadruple the change in length that rod #2 has.

D

Explanation:

For Rod 1

length,diameter and Tension is L, d and T

for Rod 2 length,diameter and Tension is 2L, 2d and 2T

Change in Length is given by

where P=load

L=length

A=area of cross-section

E=young's Modulus

since both are aluminium rod therefore E is common

Thus extension in both the rods are same

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.