A lightning bolt occurs when billions of protons are transferred at the same time. ___________________

An alert physics student stands beside the tracks as a train rolls slowly past. He notes that the frequency of the train whistle

Dovator [93]

Answer:The velocity of the train is 3.84m/s

Explanation:

According to the Doppler effect, if the source is moving towards you then the apparent frequency of the sound emitted by the source is higher and if the source is moving away from you then the apparent frequency of the sound emitted by the source is smaller.

This is given by:

fo = V +-Vo/ V +-Vo × source

Where fo= observed frequency

V= velocity of sound

Vo= vo it of the observer

fsource= frequency the source

Given:

Observed frequency of the approaching train fo1= 452Hz

The observed frequency of train= fo2= 442Hz

Velocity of sound= 334m/s

Velocity of source=?

Train approaching the observer is given by:

fo1= V/(V - Vs)× source ...eq1

Train passes the student is given by:

fo2= V/(V - Vs)×source ...eq2

Divide eq1 by eq2

452/442 = (343+Vs)/(343 - Vs)

1.02 =(343+Vs)/(343 -Vs)

Cross multiply

1.02(343- Vs) = 343 + Vs

350.76 - 1.02Vs = 343 + Vs

Collecting like terms

350.76 -343= 1.02Vs+ Vs

7.76 = 2.02Vs

Vs= 7.76/2.02

Vs= 3.84m/s

4 0

3 years ago

A box slides down a frictionless plane inclined at an angle θ above the horizontal. The gravitational force on the box is direct

tamaranim1 [39]

Answer:

D) Vertically.

Explanation:

A free body diagram is used to represent all the forces acting in a body. forces like, the force of gravity as a result of the gravitational interaction between the object and the Earth (W), the frictional force opposite to the movement of the object ( $F_{r}$ ), the normal force due to the plane and the object (N) and the force applied to start the movement in a particular direction (F).

As is show in the free body diagram of the system, W, which is the weight of the body as a consequence of the gravitational force, is at an angle $\theta$ below the inclined plane. that angle between the plane and the x axis is the same that the one of the inclined plane with respect to the horizontal, Since its sides are perpendicular.

Notice how W goes always in the direction to the center of mass of Earth in a vertical path (For comparison see figure (a) and (b)).

4 0

3 years ago

Ok plz answer and tell me how to do it

kirza4 [7]

Answer: 25N

method: total force in the right hand direction is 100N and total force in the left hand direction is 125N. To get the net force, we add forces if they are in the same direction and substract if they are in opposite directions. since 100N and 125N are in opposite directions, we substract the larger value from the smaller value. Then we get 25N in the left hand direction as the final answer.

4 0

3 years ago

Corn plants and milkweed plants grow in the same area. Over several years, the milkweed plants have taken over the field and the

erma4kov [3.2K]

Weeds are very important agronomically because they reduce the yield of crops in three ways: by competing with the crop for water, light and nutrients, by interfering with crop harvest, and by contaminating harvested products with weed seeds and toxins. Weeds can reduce yield up to 50% and are responsible for millions of dollars in crop losses each year.

It’s biotic factor would be competition as Competition can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another.

3 0

3 years ago

Read 2 more answers

What is the wavelength of an earthquake wave if it has a speed of 12 km/s and a frequency of 15 Hz

professor190 [17]

First change km/ s into m/s, then use the formula
Lambda = velocity/ frequency

3 0

3 years ago

A lightning bolt occurs when billions of protons are transferred at the same time. ____________________