All categories

3 years ago

List all the forces that act on a hot air ballon when it is in the sky

2 answers:

6 0

Down ... gravity
Up ....... buoyancy

When these are equal, then the balloon either stays at the same altitude,
or moves up or down at a constant rate.

Horizontal ... wind

When wind is not zero, the balloon accelerates in the direction of the wind.

nikdorinn [45]3 years ago

3 0

Gravity, acceleration, kinetic energy, the atmosphere

You might be interested in

1. A particle has a mass of 10 kg and a velocity of 5 m/s. What is the momentum of the particle?

Aleksandr [31]

✰ Concept :-

⠀

We know that momentum is the product of mass and velocity. Thus, by the following definition, we get :-

⠀

$\qquad \maltese \: \underline{ \boxed{ \purple{ \sf Momentum = Mass \times Velocity }}} \: \star$

⠀

✰ Given Information :-

⠀

A particle has mass 10 kg
Moving with velocity 5 m/s

⠀

✰ To Find :-

⠀

The momentum of the particle

⠀

✰ Solution :-

⠀

Using the formula from the concept section, we get :-

⠀

$\sf \longrightarrow Momentum =10 \: kg \times 5 \: {m}^{ - 1} ~~~ \\ \\ \\\sf \longrightarrow Momentum = {50~kg \: ms}^{ - 1} \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \\ \sf \longrightarrow \underline{ \boxed{ \frak{ \orange{Momentum = {50 ~kg\: ms}^{ - 1} }}}} \: \star \: \: \: \: \: \: \\ \\$

Thus, the momentum of the particle is 50 kg m/s.

⠀

$\underline{ \rule{230pt}{2pt}} \\ \\$

8 0

2 years ago

The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light

Vlada [557]

Answer:

Minimum required frequency is υmin = 654.9 x 10¹² Hz

Explanation:

The energy of a photon is given by the equation:

E = hυ

where,

E = energy of photon

h = Plank's Constant = 6.626 x 10⁻³⁴ J.s

υ = frequency

The minimum energy of photon, must be equal to the work function of Calcium.

Emin = ∅₀ = h(υmin)

υmin = ∅₀/h

where,

υmin = minimum frequency

∅₀ = work function = 4.34 x 10⁻¹⁹ J

Therefore,

υmin = 4.34 x 10⁻¹⁹ J/6.625 x 10⁻³⁴ J.s

υmin = 654.9 x 10¹² Hz

3 0

3 years ago

A 1200-kg SUV is moving alone a straight highway at 12.0 m/s. Another car, with mass 1800 kg and speed 20.0 m/s, has its center

andreev551 [17]

Answer:

A) d = 24 m

B) 50400 kg.m/s

C) v₀ = 16.8 m/s

D) 50400 kg.m/s. It's equal to the momentum found in part B.

Explanation:

We are given;

Mass of station wagon;m1 = 1200 kg Velocity; V = 12 m/s

Mass of car; m2 = 1800 kg

Velocity of car; v2 = 20 m/s

a ) Let centre of mass of car and station wagon be at a distance d from wagon

Thus,

If we take moment of weight about it, we have;

1200 x d = 1800 x ( 40 - d )

Where, d is the position of the center of mass of the system consisting of the two cars

Thus,

1200d = 72000 - 1800d

1200d + 1800d = 72000

3000 d = 72,000

d = 72,000/3000

d = 24 m

b ) Total momentum= m1•v1 + m2•v2

= (1200 x 12) + (1800 x 20)

= 14400 + 36000

= 50400 kg.m/s

c ) Let speed of centre of mass be v₀

Thus,

v₀ = (m1•v1 + m2•v2)/(m1 + m2)

v₀ = 50400/(1200 + 1800)

v₀ = 50400/3000

v₀ = 16.8 m/s

d) System Total momentum = velocity of centre mass x total mass

Thus,

Total momentum = v₀(m1 + m2)

= 16.8(3000) = 50400 kg.m/s .

This value is equal to what was calculated in part b

8 0

3 years ago

Which type of rock commonly contains fossils? A. sedimentary B. igneous C. metamorphic D. plutonic

Komok [63]

Answer:

A. Sedimentary

Explanation:

I took the test and got this correct. Hopefully this helps you!

3 0

3 years ago

In which case does viscosity play a dominant role? Case A: a typical bacterium (size ~ 1 mm1 mm and velocity ~ 20 mm/s20 mm/s) i

My name is Ann [436]

Answer:

Case A

Explanation:

given,

size of bacteria = 1 mm x 1 mm

velocity = 20 mm/s

size of the swimmer = 1.5 m x 1.5 m

velocity of swimmer = 3 m/s

Viscous force

$F = \eta A \dfrac{dv}{dx}$

for the bacteria

$F = \eta \times 10^{-6}\times 20\times 10^{-3}$

$F =2\times 10^{-8} \eta\ N$

for the swimmer

$F = \eta \times 1.5^2\times 3$

$F =6.75 \eta\ N$

from the above force calculation

In case B inertial force that represent mass is more than the inertial force in case of bacteria.

Viscous force is dominant in case of bacteria.

So, In Case A viscous force will be dominant.

5 0

3 years ago