1) B. Energy is the ability to do work
2) C. Energy is conserved, it just goes from one form to another.
3) Work = Force x displacement
= 300 x 100 = 30,000 Joules
4) leaning a brick because no displacement is taking place.
5) They change the amount/strength or direction of the force needed.
6) Less force is needed and applied over a longer distance.
7) Heat is the flow of thermal energy from one object to another.
Answer:
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Answer:
K = ρL²g
Explanation:
Consider L as the length of the raft inside the water when the raft is displaced through additional distance y;
Then:
F = upthrust ( restoring force) = weight of the liquid displaced.

where;
A = L²

F = ky.
Then,


Divide both sides by y
K = ρL²g
Answer:
Explanation:
a )
The stored elastic energy of compressed spring
= 1 / 2 k X²
= .5 x 19.6 x (.20)²
= .392 J
b ) The stored potential energy will be converted into gravitational potential energy of the block earth system when the block will ascend along the incline . So change in the gravitational potential energy will be same as stored elastic potential energy of the spring that is .392 J .
c ) Let h be the distance along the incline which the block ascends.
vertical height attained ( H ) =h sin30
= .5 h
elastic potential energy = gravitational energy
.392 = mg H
.392 = 2 x 9.8 x .5 h
h = .04 m
4 cm .
=