For this case, in the next item we have gravitational potential energy:
An apple in a tree.
Suppose we define our reference system at the floor level.
Suppose the apple is at a height h from the floor and has mass m.
The gravitational potential energy of the apple is given by:
U = mgh
Where,
m: apple mass
h: height of the apple with respect to the floor
g: acceleration due to gravity
Answer:
C) an apple on a tree
Answer:
a = 3.27 m/s²
F = 32.7 N
Explanation:
Draw a free body diagram. There are three forces:
Weight force mg pulling straight down.
Normal force N pushing perpendicular to the slope.
Friction force F pushing parallel up the slope.
Sum of forces in the parallel direction:
∑F = ma
mg sin θ − F = ma
Sum of torques about the cylinder's axis:
∑τ = Iα
Fr = ½ mr²α
F = ½ mrα
Since the cylinder rolls without slipping, a = αr. Substituting:
F = ½ ma
Two equations, two unknowns (a and F). Substituting the second equation into the first:
mg sin θ − ½ ma = ma
Multiply both sides by 2/m:
2g sin θ − a = 2a
Solve for a:
2g sin θ = 3a
a = ⅔ g sin θ
a = ⅔ (9.8 m/s²) (sin 30°)
a = 3.27 m/s²
Solving for F:
F = ½ ma
F = ½ (20 kg) (3.27 m/s²)
F = 32.7 N
Answer:
D. is always perpendicular to the surface of the conductor
Explanation:
1) Answer is (D) option. Electric field just outside surface of charged conductor is normal to conductor at that point.
It can be explained on the basis of the fact that, Electric field inside conductor under static condition is zero. As a result potential difference between any two points with in conductor is zero. So whole of conductor is equipotential body.
Equipotential surface and Electric field lines always cut at 90 degrees to each other. Conductor being equipotential body, Electric field lines starting or terminating at conductor must be normal to surface. Hence electric field just outside conductor is perpendicular or normal to surface.
To solve this problem it is necessary to apply the concepts related to wavelength as a function of speed and frequency. In mathematical terms it can be expressed as

Where,
v = Velocity
f = Frequency
According to our values the frequency (f) is 320Hz and the speed (v) is 339m / s.
Replacing in the given equation we have to,

Therefore the wavelength of this sound wave is 1.06m