The horizontal velocity of a projectile when it is in the air is __

A balloon filled with helium gas has an average density of rhob = 0.22 kg/m3. The density of the air is about rhoa = 1.23 kg/m3.

MissTica

Answer:

$a=g\left(\frac{\rho_a}{\rho_b}-1\right)$

45.03681 m/s²

Explanation:

$F_b$ = Buoyant force

W = Weight of the balloon

$\rho_a$ = Density of air = 1.23 kg/m³

$\rho_b$ = Density of balloon = 0.22 kg/m³

$v_a$ = Volume of air

$v_b$ = Volume of balloon

$F_b=\rho_av_bg$

$W=\rho_bv_bg$

g = Acceleration due to gravity = 9.81 m/s²

The net force acting on the balloon is

$F=F_b-W\\\Rightarrow F=\rho_av_bg-\rho_bv_bg\\\Rightarrow \rho_bv_ba=\rho_av_bg-\rho_bv_bg\\\Rightarrow \rho_bv_ba=v_bg(\rho_a-\rho_b)\\\Rightarrow a=\frac{g}{\rho_b}(\rho_a-\rho_b)\\\Rightarrow a=g\left(\frac{\rho_a}{\rho_b}-1\right)$

The equation is $a=g\left(\frac{\rho_a}{\rho_b}-1\right)$

$a=g\left(\frac{\rho_a}{\rho_b}-1\right)\\\Rightarrow a=9.81\times \left(\frac{1.23}{0.22}-1\right)\\\Rightarrow a=45.03681\ m/s^2$

The acceleration of the balloon is 45.03681 m/s²

8 0

3 years ago

Describe the movement of a compass needle when a magnet is placed in proximity to it, then moved away again.

Schach [20]

When the magnet is near, the compass turns and points to it. When the magnet is moved away, the compass turns back to point north and south.

4 0

3 years ago

I NEED HELP BADLY

Marrrta [24]

Answer:

a) Andrea's initial momentum, 200 kg m/s

b) Andrea's final momentum, 0

c) Impulse, = - 200 Ns

d) The force that the seat belt exerts on Andrea, - 400 N

Explanation:

Given data,

The initial velocity of the car is, u = 40 m/s

The mass of Andrea, m = 50 kg

The time period of deceleration, a = 0.5 s

The final velocity of the car, v = 0

a) Andrea's initial momentum,

p = mu

= 50 x 40

= 200 kg m/s

b) Andrea's final momentum

P = mv

= 50 x 0

= 0 kg m/s

c) Impulse

I = mv - mu

= 0 - 200

= - 200 Ns

The negative sign indicated that the momentum is decreased.

d) The force that the seat belt exerts on Andrea

F = (mv - mu)t

= (0 - 200) / 0.5

= - 400 Ns

Hence,the force that the seat belt exerts on Andrea is, - 400 N

7 0

3 years ago

Water flows with constant speed through a garden hose that goes up to 27.5 cm high. if the water pressure is 132kpa at the botto

sergejj [24]

Answer:

The pressure at the top of the step is 129.303 kilopascals.

Explanation:

From Hydrostatics we find that the pressure difference between extremes of the water column is defined by the following formula, which is a particular case of the Bernoulli's Principle ( $v_{bottom}\approx v_{top}$ ):

$p_{bottom}-p_{top} = \rho\cdot g\cdot \Delta h$ (1)

$p_{bottom}$ , $p_{top}$ - Total pressures at the bottom and at the top, measured in pascals.

$\rho$ - Density of the water, measured in kilograms per cubic meter.

$\Delta h$ - Height difference of the step, measured in meters.

If we know that $p_{bottom} = 132000\,Pa$ , $\rho = 1000\,\frac{kg}{m^{3}}$ , $g = 9.807\,\frac{m}{s^{2}}$ and $\Delta h = 0.275\,m$ , then the pressure at the top of the step is:

$p_{top} = p_{bottom}-\rho\cdot g\cdot \Delta h$

$p_{top} = 132000\,Pa-\left(1000\,\frac{kg}{m^{3}} \right)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (0.275\,m)$

$p_{top} = 129303.075\,Pa$

$p_{top} = 129.303\,kPa$

The pressure at the top of the step is 129.303 kilopascals.

6 0

3 years ago

The wavelength of light that has a frequency of 1.20 × 1013 s-1 is ________ m.

klio [65]

The relationship between frequency and wavelength for an electromagnetic wave is
$c=f \lambda$
where
f is the frequency
$\lambda$ is the wavelength
$c=3 \cdot 10^8 m/s$ is the speed of light.

For the light in our problem, the frequency is $f=1.20 \cdot 10^{13} s^{-1}$ , so its wavelength is (re-arranging the previous formula)
$\lambda= \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{1.20 \cdot 10^{13} s^{-1}}= 2.5 \cdot 10^{-5}m$

8 0

3 years ago

The horizontal velocity of a projectile when it is in the air is ___.