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makvit [3.9K]
3 years ago
15

A train is traveling at 30.0 m/sm/s relative to the ground in still air. The frequency of the note emitted by the train whistle

is 262 HzHz. The speed of sound in air should be taken as 344 m/sm/s. Part A What frequency fapproachfapproachf_approach is heard by a passenger on a train moving at a speed of 18.0 m/sm/s relative to the ground in a direction opposite to the first train and approaching it
Physics
1 answer:
REY [17]3 years ago
3 0

Answer:

Explanation:

The problem is based on Doppler's effect , for which expression is as follows

n = \frac{n_o(V+v_o)}{(V-v_s)}

n is apparent frequency , n₀ is original frequency , V is velocity of light , v₀ is velocity of observer and v_s is velocity of source , both coming towards each other.

Putting the values

n = \frac{262(344+18)}{(344-30)}

n = 302 .

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Why is an object's density expressed as a relationship between two units?
vfiekz [6]
Probably for kind of the same reason that speed is expressed as a
relationship between two units.  You know, like miles per hour .

I guess the only reason is because no single unit has been invented
to describe density.

The rate of doing work or using energy would always be expressed
as a relationship between two units ... we would say that the rate of
work is "(so many) joules per second".  But the "watt" was invented,
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Let's try it out:
 
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5 0
3 years ago
The car starts from a room with a constant acceleration of 5 ms-2. What path will it pass in 6 seconds and what speed will it re
Kobotan [32]

Answer: The speed will be  30 m/s .

Explanation:

Given: Initial velocity of the car: u = 0 m/s

Constant Acceleration: a = 5 m/s²

Time: t= 6 seconds

To find: Final velocity(v)

Formula:  v = u+at

Substitute values in the formula, we get

v=  0+(5)(6) m/s

⇒ v= 30 m/s

i.e. Final velocity = 30 m/s

Hence, the speed will be 30 m/s .

4 0
2 years ago
A. In one short sentence, explain why we call the force of gravity an attractive force.
kondor19780726 [428]

Answer:

Explanation:

(a) The force of gravity is called an attractive force because it is the force (although weak) in which a planetary body or matter uses to attract an object towards itself.

(b) Yes, it does and the formula for force of gravity between any two object is

F = G\frac{m1m2}{r}

where m1 and m2 are masses of the first and second object respectively

r is the distance between the center of the two masses

G is the gravitational constant

3 0
3 years ago
Two objects experienced the same displacement in the same amount of time. The two objects must have the same -
nikdorinn [45]

If two object experiences the same displacement at the same time, the two objects must have the same average velocity.

The average velocity of an object is defined as the change in displacement per change in time of motion. This can be written as follows;

avg. \ velocity = \frac{\Delta \ displacement }{\Delta \ time} \\\\V = \frac{\Delta \ x}{\Delta t}

If two object experiences the same displacement at the same time, it means that the change in displacement with time is constant.

\frac{\Delta x_1}{\Delta t_1} = \frac{\Delta x_2}{\Delta t_2} = V_{avg}

Thus, we can conclude that if two object experiences the same displacement at the same time, the two objects must have the same average velocity.

Learn more here: brainly.com/question/23856383

6 0
3 years ago
A coil of area 0.320 m2 is rotating at 100 rev/s with the axis of rotation perpendicular to a 0.430 T magnetic field. If the coi
weqwewe [10]

Answer:

The maximum  emf generated in the coil is 60527.49 V

Explanation:

Given;

area of coil, A = 0.320 m²

angular frequency, f = 100 rev/s

magnetic field, B = 0.43 T

number of turns, N = 700 turns

The maximum emf generated in the coil is calculated as,

E = NBAω

where;

ω is the angular speed = 2πf

E = NBA(2πf)

Substitute in the given values and solve for E

E = 700 x 0.43 x 0.32 x 2π x 100

E = 60527.49 V

Therefore, the maximum  emf generated in the coil is 60527.49 V

8 0
3 years ago
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