Answer: A crest is the highest point the medium rises to and a trough is the lowest point the medium sinks to. It is also a point on the wave where the displacement of the medium is at a maximum.
Answer:
2. at the lowest point
Explanation:
The motion of the pendulum is a continuous conversion between kinetic energy (KE) and gravitational potential energy (GPE). This is because the mechanical energy of the pendulum, which is sum of KE and GPE, is constant:
E = KE + GPE = const.
Therefore, when KE is maximum, GPE is minimum, and viceversa.
So, the point of the motion where the KE is maximum is where the GPE is minimum: and since the GPE is directly proportional to the heigth of the bob:

we see that GPE is minimum when the bob is at the lowest point,so the correct answer is
2. at the lowest point
Answer:
V=2.8 ml
Explanation:
volume of the cube is it would be 20.3 - 17.5 ml so 2.8 ml.
At the point of maximum displacement (a), the elastic potential energy of the spring is maximum:

while the kinetic energy is zero, because at the maximum displacement the mass is stationary, so its velocity is zero:

And the total energy of the system is

Viceversa, when the mass reaches the equilibrium position, the elastic potential energy is zero because the displacement x is zero:

while the mass is moving at speed v, and therefore the kinetic energy is

And the total energy is

For the law of conservation of energy, the total energy must be conserved, therefore

. So we can write

that we can solve to find an expression for v:
Answer:
= 7.07 m
Explanation:
The Tarzan reaches bottom of swing after descending 2.5 m,
change in his potential energy equals his kinetic energy at bottom of swing
m g h = (1/2) m v² ,
hence speed v of Tarzan at bottom of swing is given as
v = ( 2 g h )1/2
= ( 2 × 9.8 × 2.5 )1/2
= 7 m/s
At the bottom of swing, if the vine breaks, then he is moving with horizontal velocity 7 m/s in gravitational field.
If vertical distance from ground to bottom of swing is 5 m, then time t for Tarzan to reach ground is given by
S = (1/2)g t2 or t = (2S/g)1/2
= ( 2 × 5 / 9.8 )1/2
= 1.01 s
Horizontal distance traveled by Tarzan = 1.01 × 7
= 7.07 m