Work = force x distance (displacement) or the change in Kinetic energy
Carrying a box down a corridor has no external force acting on the box and therefore no work is being done.
Pushing against a locked door doesn't displace the door, so no work is being done.
Suspending a heavy weight with a strong chain requires, no force and actually prevents a force from acting on the chain.
Pulling a trailer up a hill on the other hand requires a person to apply a force to the trailer and displace it up the hill and therefore it requires work.
Answer:
When her hands extends, her momen of inertia is 
.
Explanation:
Given that,
Initial angular speed, 
Initial moment of inertia, 
Final angular speed, 
Initially, a skater rotates with her arms crossed and finally she extends her arms. The momentum remains conserved. Using the conservation of momentum as :
is final moment of inertia
So, when her hands extends, her momen of inertia is . Hence, this is the required solution.
Its an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell.
Answer:
a.) volume = 70cm^3
b.) mass = 805 grams
Explanation:
see the explanation in attachment.
