Answer:
67,032 J
Explanation:
According to the law of conservation of energy, the kinetic energy of the boulder just before hitting the Roadrunner (at ground level) will be equal to the gravitational potential energy of the boulder at the top of the cliff, therefore:
where
m is the mass of the boulder
g is the acceleration of gravity
h is the height of the cliff
Here we have
m = 76 kg
g = 9.8 m/s^2
h = 90 m
Substituting,
Answer:
an electric motor
Explanation:
electric motor contains an electromagnet that can rotate between poles of a magnet.
Answer:
Gases
Explanation:
Gas has particles that are all very far apart and are moving quickly causing them to have very little to no attraction.
Correct answer is:
"Work is negative, the object did work on the environment, and the energy of the system decreases. "
In fact, the work-energy theorem states that the work done is equal to the variation of kinetic energy:
where W is the work, Kf the final kinetic energy and Ki the initial kinetic energy. Since the kinetic energy depends on the velocity v by:
and since the final velocity is less than the initial velocity,
is negative (the kinetic energy of the system is decreased), and the work is negative.This also means that the object did work on the environment: in fact, by doing work, the object gave part of its kinetic energy to the environment, and so its kinetic energy decreased.
