Answer: The answer is A.
Explanation:
Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be greater than your normal weight at rest.
Approximately 15 m/s is the speed of the car.
<u>Explanation:</u>
<u>Given:</u>
speed of sound - 343 m/s
You detect a frequency that is 0.959 times as small as the frequency emitted by the car when it is stationary. So, it can be written as,
If there is relative movement between an observer and source, the frequency heard by an observer differs from the actual frequency of the source. This changed frequency is called the apparent frequency. This variation in frequency of sound wave due to motion is called the Doppler shift (Doppler effect). In general,
Where,
- Observed frequency
f – Actual frequency
v – Velocity of sound waves
– Velocity of observer
- velocity of source
When source moves away from an observer at rest (
), the equation would be
By substituting the known values, we get
Approximately 15 m/s is the speed of the car.
Answer:
True
Explanation:
If a thin, spherical, conducting shell carries a negative charge, We expect the excess electrons to mutually repel one another, and, thereby, become uniformly distributed over the surface of the shell. The electric field-lines produced outside such a charge distribution point towards the surface of the conductor, and end on the excess electrons. Moreover, the field-lines are normal to the surface of the conductor. This must be the case, otherwise the electric field would have a component parallel to the conducting surface. Since the excess electrons are free to move through the conductor, any parallel component of the field would cause a redistribution of the charges on the shell. This process will only cease when the parallel component has been reduced to zero over the whole surface of the shell
According to Gauss law
∅ = EA =-Q/∈₀
Where ∅ is the electric flux through the gaussian surface and E is the electric field strength
If the gaussian surface encloses no charge, since all of the charge lies on the shell, so it follows from Gauss' law, and symmetry, that the electric field inside the shell is zero. In fact, the electric field inside any closed hollow conductor is zero
Explanation:
Work is the dot product of the force and displacement vectors.
W = F · d
In other words, it is the force times the parallel component of the distance.
W = F d cos θ, where θ is the angle between the force and distance.
