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defon
3 years ago
15

An element has 4 protons, 5 neutrons, and 4 electrons. What is the atomic mass of the element

Physics
1 answer:
vfiekz [6]3 years ago
7 0
Beryllium: mass number of an atom = number of neutron + number of proton in the nucleus = 5+4=9
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Use appropriate units and significant figures.  USE THE LAW OF COSINES AND LAW OF SINES.
N76 [4]

Answer:

The resultant velocity is 86.1 mi/h.    

Explanation:

The law of cosines is given by:

c^{2} = a^{2} + b^{2} - 2abcos(\theta)

Where:

c: is the resultant velocity =?

a: is the velocity of the plane = 75.0 mi/h

b: is the velocity of the wind = 15.0 mi/h  

θ: is the angle between "a" and "b"                          

The angle between "a" and "b" can be found as follows:

\theta = 180.0 - 46.0 = 134.0 ^{\circ}

Now, by using the law of cosines we have:

c^{2} = (75.0)^{2} + (15.0)^{2} - 2*75.0*15.0*cos(134.0) = 7413.0

c = 86.1 mi/h    

Therefore, the resultant velocity is 86.1 mi/h.    

The law of sines is:

\frac{a}{sin(\gamma)} = \frac{b}{sin(\alpha)} = \frac{c}{sin(\theta)}

Where:

γ: is the angle between "b" and "c"

α: is the angle between "a" and "c"

So, if we want to find "c" by using the law of sines, we need to know another angle besides θ (γ or α), and the statement does not give us.

I hope it helps you!        

3 0
3 years ago
Fast need answers <br>Find the amount of force if the body has pressure of 178 Pa on 18 mm²​
guajiro [1.7K]

Answer:

Force = 3.204Newton

Explanation:

Given the following data;

Pressure = 178

Area = 18 mm² to meter = 18/1000 = 0.018 m²

To find the force;

Force = pressure * area

Force = 178 * 0.018

Force = 3.204 Newton.

4 0
3 years ago
What properties of sound determine the volume of sound? Is this affected by the motion of the sound source?
Alik [6]
The amplitude determines the volume of the sound. This isn't affected by the motion of the sound source.
Hope this helps
6 0
3 years ago
The diagram shows the parabolic path of a projectile that leaves the foot of a kicker with a horizontal velocity of 15 m/s and a
rusak2 [61]

Answer:

I would increase the horizontal velocity or the vertical velocity or both to make the ball go the extra distance to cross the goal line.

Explanation:

In order to increase the horizontal distance covered by the ball, we need to examine the variables involved in the formula of range of projectile. The formula for the range of projectile is given as follows:

R = V₀² Sin 2θ/g

where, g is a constant on earth (acceleration due to gravity) and θ is the angle of ball with ground at the time of launching. The value of θ should be 45° for maximum range. In this case we do not know the angle so, we can not tell if we should change it or not.

The only parameter here which we can increase to increase the range is launch velocity (V₀). The formula for V₀ in terms of horizontal and vertical components is as follows:

V₀ = √(V₀ₓ² + V₀y²)

where,

V₀ₓ = Horizontal Velocity

V₀y = Vertical Velocity

Hence, it is clear from the formula that we can increase both the horizontal and vertical velocity to increase the initial speed which in turn increases the horizontal distance covered by the ball.

<u>Therefore, I would increase the horizontal velocity or the vertical velocity or both to make the ball go the extra distance to cross the goal line.</u>

4 0
3 years ago
Alvin paddled for 44 hours with a 33​-km/h current to reach a campsite. The return trip against the same current took 77 hours.
sveta [45]

Answer:

121km/h

Explanation:

Let speed of boat=xkm/h

Speed of water flow=33 km/h

Speed upstream=(x-33)km/h

Speed downstream=(x+33)km/h

Time=44 hrs

Time =77 hrs

We have to find the speed of boat.

Distance=Speed\times time

Using the formula

Upstream distance=Downstream distance

(x-33)\times 77=(x+33)\times 44

77x-2541=44x+1452

77x-44x=1452+2541

33x=3993

x=\frac{3993}{33}=121

Hence, the speed of boat=121km/h

8 0
3 years ago
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