All categories

3 years ago

Boats use echo sounders. Pulses of sound waves are reflected by the sea bed and

Physics

1 answer:

Sati [7]3 years ago

4 0

Answer: depth = 3.75 m

Explanation:

Taken the speed of the sound in sea to be V = 1500 m/s

The time between an echo sounder sending and receiving a pulse is 0.005 s. That is,

Total time T = 0.005

Formula for echo is:

V = 2X/T

Where X = distance covered

Substitute V and T into the formula

1500 = 2X/0.005

Cross multiply

7.5 = 2X

Make X the subject of formula

X = 7.5/2

X = 3.75 m

Therefore, the depth of the sea is 3.75 m

You might be interested in

If you're a psychologist who is fascinated by how alcohol acts on the nervous system to alter perception, you probably follow th

Nataly_w [17]

Biological perspective

7 0

3 years ago

Physical fitness is related to our ability to carry out daily tasks without being too tired or sore. Please select the best answ

WARRIOR [948]

Physical fitness is related to our ability to carry out daily tasks without being too tired or sore. This statement is TRUE.

<h3>Further explanation </h3>

Good physical fitness means that you can perform daily activities, occupations, and sports. This condition will be achieved through good nutrition, regular exercise, and have enough rest.

The benefit of physical activity and exercise can be immediate as well as long-term. Most importantly, regular activity can improve your quality of life.There are four types of physical fitness:

Cardiovascular exercise: exercises that increase the work of the heart and lungs, such as walking, jogging, step aerobics, swimming, and biking. Cardio activity improves your heart/lung function and muscle mass.
Muscular strength exercise: this exercise is to build overall strength and muscle mass.
Joint flexibility exercise: this exercise to help the ability of the muscle group can be stretched or joint can be moved, for example: bending, lifting and driving. Stretching can reduce the risk of injury.
Muscular endurance exercise: this exercise to find out how many repetitions of exercises a person can perform, such as push-ups and sit-ups.

<h3>Learn more </h3>

Physical activity brainly.com/question/1400373

Environment factors that affecting physical fitness brainly.com/question/982205

Factors that influence physical fitness brainly.com/question/1488529

Keywords: physical fitness, the definition of physical fitness, physical activity

7 0

4 years ago

Read 2 more answers

An automobile travels on a straight road for 40 km at 30 km/h. It then continues in the same direction for another 40 km at 60 k

Butoxors [25]

Answer:

The average velocity is 40km/h.

Explanation:

The average velocity is $\bar{v}=\frac{\Delta x }{\Delta t}$ , where $\Delta x$ is the distance traveled and $\Delta t$ the time elapsed.

The distance traveled is clearly 80km since it's all done in the same direction, we only need to know the time elapsed. For this we calculate the time elapsed on the first part, and add it to the time elapsed on the second part using always the formula $\Delta t=\frac{\Delta x }{v}$ , where v is the velocity on each part, which is constant.

The time elapsed for the first part is $\Delta t_1=\frac{40 km}{30km/h}=\frac{4}{3}h$ , and the time elapsed for the second part is $\Delta t_2=\frac{40 km}{60km/h}=\frac{2}{3}h$ , giving us a total time of $\Delta t_1+\Delta t_2=\frac{4}{3}h+\frac{2}{3}h$ =2h.

Finally, we can calculate the average velocity: $\bar{v}=\frac{80km}{2h}=40km/h$ .

6 0

3 years ago

What is the total energy q released in a single fusion reaction event for the equation given in the problem introduction? use c2

kkurt [141]

Answer:

$4.3\cdot 10^{-12} J$

Explanation:

The fusion reaction in this problem is

$4^1_1H \rightarrow ^4_2He +2e^+$

The total energy released in the fusion reaction is given by

$\Delta E = c^2 \Delta m$

where

$c=3.0\cdot 10^8 m/s$ is the speed of light

$\Delta m$ is the mass defect, which is the mass difference between the mass of the reactants and the mass of the products

For this fusion reaction we have:

$m(^1_1H)=1.007825u$ is the mass of one nucleus of hydrogen

$m(^4_2 He)=4.002603u$ is the mass of one nucleus of helium

So the mass defect is:

$\Delta m =4m(^1_1 H)-m(^4_2 He)=4(1.007825u)-4.002603u=0.028697u$

The conversion factor between atomic mass units and kilograms is

$1u=1.66054\cdot 10^{-27}kg$

So the mass defect is

$\Delta m =(0.028697)(1.66054\cdot 10^{-27})=4.765\cdot 10^{-29}kg$

And so, the energy released is:

$\Delta E=(3.0\cdot 10^8)^2(4.765\cdot 10^{-29})=4.3\cdot 10^{-12} J$

6 0

3 years ago

A Texas rancher wants to fence off his four-sided plot of flat land. He measures the first three sides, shown as A, B, and C in

xz_007 [3.2K]

The answer:
the full question is as follow:
<span>A Texas rancher wants to fence off his four-sided plot of flat land. He measures the first three sides, shown as A, B, and C in Figure below , where A = 4.90 km and θC = 15°. He then correctly calculates the length and orientation of the fourth side D. What is the magnitude and direction of vector D?

As shown in the figure,
A + B + C + D = 0, so to find the </span>magnitude and direction of vector D, we should follow the following method:
D = 0 - (A + B + C) ,
let W = - (A + B + C), so the magnitude and direction of vector D is the same of the vector W characteristics

Magnitude
A + B + C = <span> (4.90cos7.5 - 2.48sin16 - 3.02cos15)I</span>
<span>+ (-4.9sin7.5 + 2.48cos16 + 3.02sin15)J
</span>= 1.25I +2.53J
the magnitude of W= abs value of (A + B + C) = sqrt (1.25² + 2.53²)
= 2.82

the direction of D can be found by using Dx and Dy value
we know that tan<span>θo = Dx / Dy = 1.25 / 2.53 =0.49
</span>tanθo =0.49 it implies θo = arctan 0.49 = 26.02°

direction is 26.02°

4 0

3 years ago