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3 years ago

Which equation is used to determine the density of a substance

Physics

1 answer:

9966 [12]3 years ago

8 0

Density = (mass)/(volume)

IF 'D' means density, 'M' means mass, and 'V' means volume, then choice-A is the equation to use.

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A projectile is fired into the air from the top of a 200-m cliff above a valley as shown below. Its initial velocity is 60 m/s a

anastassius [24]

a) y(max) = 337.76 m

b) t₁ = 5.30 s the time for y maximum

c)t₂ = 13.60 s time for y = 0 time when the fly finish

d) vₓ = 30 m/s vy = - 81.32 m/s

e)x = 408 m

Equations for projectile motion:

v₀ₓ = v₀ * cosα v₀ₓ = 60*(1/2) v₀ₓ = 30 m/s ( constant )

v₀y = v₀ * sinα v₀y = 60*(√3/2) v₀y = 30*√3 m/s

a) Maximum height:

The following equation describes the motion in y coordinates

y = y₀ + v₀y*t - (1/2)*g*t² (1)

To find h(max), we need to calculate t₁ ( time for h maximum)

we take derivative on both sides of the equation

dy/dt = v₀y - g*t

dy/dt = 0 v₀y - g*t₁ = 0 t₁ = v₀y/g

v₀y = 60*sin60° = 60*√3/2 = 30*√3

g = 9.8 m/s²

t₁ = 5.30 s the time for y maximum

And y maximum is obtained from the substitution of t₁ in equation (1)

y (max) = 200 + 30*√3 * (5.30) - (1/2)*9.8*(5.3)²

y (max) = 200 + 275.40 - 137.64

y(max) = 337.76 m

Total time of flying (t₂) is when coordinate y = 0

y = 0 = y₀ + v₀y*t₂ - (1/2)* g*t₂²

0 = 200 + 30*√3*t₂ - 4.9*t₂² 4.9 t₂² - 51.96*t₂ - 200 = 0

The above equation is a second-degree equation, solving for t₂

t = [51.96 ±√ (51.96)² + 4*4.9*200]/9.8

t = [51.96 ±√2700 + 3920]/9.8

t = [51.96 ± 81.36]/9.8

t = 51.96 - 81.36)/9.8 we dismiss this solution ( negative time)

t₂ = 13.60 s time for y = 0 time when the fly finish

The components of the velocity just before striking the ground are:

vₓ = v₀ *cos60° vₓ = 30 m/s as we said before v₀ₓ is constant

vy = v₀y - g *t vy = 30*√3 - 9.8 * (13.60)

vy = 51.96 - 133.28 vy = - 81.32 m/s

The sign minus means that vy change direction

Finally the horizontal distance is:

x = vₓ * t

x = 30 * 13.60 m

x = 408 m

5 0

2 years ago

For most people, getting 8 to 9 hours of sleep increases concentration, improves physical health, and improves one's mood.

olga2289 [7]

That statement is true

8 0

3 years ago

Read 2 more answers

Fluorine has 7 valence electrons. Which charge is its ion likely to have?(1 point)

7nadin3 [17]

Answer:

1–

Explanation:

The fluorine is the element with biggest electronegativity in the periodic table, so it usually always take an electron and gets charge 1–

5 0

2 years ago

Which is the one factor that adds to the greenhouse effect? 1. a decrease in the amount of dust in the atmosphere 2. a decrease

lukranit [14]

Answer:

an increase in gasses that absorb heat

Explanation:

Greenhouse effect refers to the gradual increase in the earth's temperature due to an increase in the concentration of certain gases in the atmosphere. These gases are called greenhouse gases and they include; water vapour, nitrogen 1 oxide, carbon IV oxide etc. Green house effect is said to occur when heat radiating outwards from the earth surface towards space is trapped close to the earth's surface due to the presence of greenhouse gases in the atmosphere.

Greenhouse effect leads to increase in the temperature of the earth, melting of polar ice caps and possibly flooding due to a rise in sea levels.

Greenhouse gases act as glass in a greenhouse. They allow heat to pass through onto the earth surface but trap the heat and prevent it from being radiated outwards back to space. Thereby increasing the surface temperature of the earth.

8 0

3 years ago

Read 2 more answers

A hiker hikes south 0.7 km. she then hikes east 2.4 km. what is the magnitude and unit of her displacement from her initial posi

Usimov [2.4K]

If you illustrate the problem, you will somewhat come up with the figure shown. The missing value is the hypotenuse of the right triangle. Using the pythagorean theorems, the value is determined to be

x = √(0.7^2 + 2.4^2)
x = 2.5 km

2.5 km is the magnitude of the distance. If you want to incorporate the displacement, the answer is reported as 2.5 km, southeast. The direction is determined from the starting point to the endpoint.

7 0

3 years ago