Answer:
1270 J
Explanation:
Recall that the mechanical energy of a system is the addition of the Potential energy and the Kinetic energy at any given time.
As the skier descends, potential energy is converted into kinetic energy, but the total mechanical energy should remain the same.
We see that it is not the case, so that difference is what has gone into thermal energy; 19500 J - 18230 J = 1270 J
Answer:
160N/m
Explanation:
According to Hooke's law which states that the extension of an elastic material is directly proportional to the applied force provided that the elastic limit is not exceeded. Mathematically,
F = ke where
F is the applied force
k is the spring constant
e is the extension
From the formula k = F/e
Since the body accelerates when the block is released, F = ma according to Newton's second law of motion.
The spring constant k = ma/e where
m is the mass of the block = 0.4kg
a is the acceleration = 8.0m/s²
e is the extension of the spring = 2.0cm = 0.02m
K = 0.4×8/0.02
K = 3.2/0.02
K = 160N/m
The spring constant of the spring is therefore 160N/m
The seat belt is applying a force in the opposite direction.
Answer:
Right Hand Rule
Explanation:
When a charged particle travels in a magnetic field, it experiences a force whose magnitude is given by:
where
q is the charge of the particle
v is the velocity
B is the magnetic field strength
is the angle between the directions of v and B
The direction of the force can be determined by using the Right Hand Rule, as follows:
- index finger: this should be put in the direction of the velocity
- middle finger: this should be put in the direction of the magnetic field
- thumb: this will give the direction of the force -> however, for a negative charge (as the electron) the direction must be reversed, so it will be opposite.
Answer: Δβ (dB) = -13.1dB
Explanation:
The intensity of sound is inversely proportional to the square of the distance between them.
I ∝ 1/r²
I₁/I₂= r₂²/r₁² .....1
When the listener increases his distance from the source by a factor of 4.49.
Then,
r₂/r₁= 4.49
From equation 1
I₁/I₂ = (4.49)²
I₁/I₂ = 20.16
I₂/I₁ = 1/20.16
The change in sound intensity in dB can be given as
Δβ (dB) = 10 log(I₂/l₁) = 10log(1/20.6) = -13.1dB
