Answer:
By the law of conservation of mechanical energy, in the absence of any drag, when the rock falls towards the ground, the potential energy gets converted to kinetic energy. Once the rock hits the ground, it does not move. This is because, the energy is dissipated as sound or heat (to the environment). The total energy remains conserved. Only the form of energy changes.
Answer:
a) 323.4J
b) 0J
c) -323.4J
Explanation:
a) W=Fd
F=ma
solve for acc. using kinematics
v^2=vo^2+2a(x)
8.41=2a(12)
4.205=a(12)
0.35=a
F=(77)(0.35)
F=26.95N
W=26.95*12...... W=323.4J
b) No acceleration, thus no force, thus no work!
c) W=Fd
F=ma
find acc. using kinematics: v^2=vo^2+2a(x)
0=(2.9^2)+2a(12)
0=8.41+2a(12)
-8.41=2a(12)
-4.205=a(12)
-0.35=a
F=(77)(-0.35)
F=-26.95N
W=(-26.95)(12)
W=-323.4J
Yes, work can be negative!
Increasing the level of an incline:
Increases final velocity
Increases the work done
Increases the initial potential energy
Increases the final kinetic energy
The velocity is extraneous information. Frequency is the inverse of the period, thus the frequency of the wave is 1/3 Hz.
