What is chronology?

The speed of sound is 344 m/sec when the air is 20 degrees Celsius how far is the source of the sound if it takes 8 seconds for

pishuonlain [190]

Answer: 2752 m

Explanation:

344*8=

5 0

3 years ago

Helppppp me it's urgent please

Luda [366]

Light bends away from the normal, because it's moving from higher to lower refractive index.

Same bend-direction as when it goes from water into air.

4 0

4 years ago

Explain why, when you have a fever, you have to keep a thermometer in your mouth for a certain length of time in order to read y

Marrrta [24]

Answer:

Because the certain period of time is needed for reaching the right temperature. After the first seconds of placing the thermometer under the tongue, readings will continue to increase and the F (or C) symbol will flash during measurement.

Explanation:

# Checking our body’s temperature with a thermometer is an easy way to see if a fever is present. There are many different types of thermometers we can use to measure temperature. When using any kind of thermometer, we need to follow the instructions that come with the thermometer in order to read the correct temperature.

# The question above is about how to use a digital thermometer, which can be used three different ways, including oral, rectal, axillary. To keep a thermometer in the mouth (place it under the tongue) for a certain length of time is the oral way to use it. This method is used for adults and children 4 and over who are able to hold thermometer in mouth. So, we call this kind of thermometer as "digital oral thermometer".

# Using a digital oral thermometer, we should follow the followings:

1- Wash the hands with soap and warm water.

2- Use a clean thermometer, one that has been washed in cold water, cleaned with rubbing alcohol, and then rinsed to remove the alcohol.

3- Do not eat or drink anything for at least five minutes before taking the temperature because the temperature of the food or beverage could make the reading inaccurate. It is neccesary to keep the mouth closed during this time.

4- Place the thermometer tip under the tongue.

5- Hold the thermometer in the same spot for about 40 seconds.

6- Rinse thermometer in cold water, clean it with alcohol and rinse again.

# In the instruction N5: Readings will continue to increase and the F (or C) symbol will flash during measurement. Usually, the thermometer will make a beeping noise when the final reading is done (usually about 30 seconds). If we are keeping track, record the temperature and the time.

And the MOST IMPORTANT THING is: we should add a degree to oral reading for the most accuracy. Rectal temperatures are considered most accurate indication of the body’s temperature.

3 0

3 years ago

A car with a velocity of 30 mph

Leokris [45]

Answer:

First calculate the deceleration making use of the formulation: V(very last speed= U(initial speed) -a(acceleration) t(ime) so 10=20- 4a. unfavourable a as decelerating. making a the acceleration the challenge by using rearranging the elements 4a= 20-10 = 10 so a=10/4 making use of Newton's 2d regulation P(stress) = M (mass) x A (acceleration). so P = 800 x 10/4 = 8000 /4 = 2000 newtons

Explanation:

4 0

3 years ago

A boat moves through the water with two forces acting on it. One is a 2.05 ✕ 103 N forward push by a motor, and the other is a 1

labwork [276]

Answer:

(a) a= 0.139 m/s²

(b) d= 4.45 m

(c) vf= 1.1 m/s

Explanation:

a) We apply Newton's second law:

∑F = m*a Formula (1)

∑F : algebraic sum of the forces in Newton (N)

m : mass (kg)

a : acceleration (m/s²)

Data

F₁= +2.05 * 10³ N : forward push by a motor

F₂= -1.87* 10³ N : resistive force due to the water.

m= 1300 kg

Calculation of the acceleration of the boat

We replace data in the formula (1):

∑F = m*a

F₁+F₂= m*a

$a=\frac{F_{1} +F_{2} }{m}$

$a= \frac{2.05*10^{3} -1.87*10^{3}}{1300}$

a= 0.139 m/s²

b) Kinematics of the boat

Because the boat moves with uniformly accelerated movement we apply the following formulas:

d= v₀t+ (1/2)*a*t² Formula (2)

vf= v₀+at Formula (3)

Where:

d:displacement in meters (m)

t : time interval (s)

v₀: initial speed (m/s)

vf: final speed (m/s)

a: acceleration (m/s² )

Data

v₀ = 0

a= 0.139 m/s²

t = 8 s

Calculation of the distance traveled by the boat in 8 s

We replace data in the formula (2)

d= v₀t+ (1/2)*a*t²

d= 0+ (1/2)*(0.139)*(8)²

d= 4.45 m

c) Calculation of the speed of the boat in 8 s

We replace data in the formula (3):

vf= v₀+at

vf= 0+( 0.139)*(8)

vf= 1.1 m/s

6 0

4 years ago