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romanna [79]
4 years ago
13

What does the term Hubble time mean in cosmology, and what is the current best calculation for the Hubble time?

Physics
1 answer:
balu736 [363]4 years ago
4 0

Hubble time in cosmology means the estimated age of the universe and the best calculation for it is T=1/H, where H is the Hubble constant
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A toy car goes over a small ramp at a horizontal velocity of 1.21 m/s and decelerates at 0.131 m/s2 while in the air. The total
xz_007 [3.2K]
We need to considerate only the horizontal component of the motion of the toy car.

The formula for the distance in a decelerated motion is:
s = s₀ + v₀·t - 1/2·a·t²

where:
s₀ = initial position = 0
v₀ = initial velocity = 1.21 m/s
t = time elapsed = 0.342 s
a = deceleration = 0.131 m/s²

Plugging in numbers:
s = 0 + 1.21×0.342 - 0.5×0.141×(0.342)²
  = 0.406 m

Hence, the toy car traveled a distance of about 41 cm.

3 0
3 years ago
Two straight wires are in parallel and carry electrical currents in opposite directions with the same magnitude of 2.0A. The dis
Veronika [31]

Answer:

Explanation:

Two straight wires

Have current in opposite direction

i1=i2=i=2Amps

Distance between two wires

r=5mm=0.005m

Length of one wire is ∞

Length of second wire is 0.3m

Force between the wire,

The force between two parallel currents I1 and I2, separated by a distance r, has a magnitude per unit length given by

F/l = μoi1i2/2πr

F/l=μoi²/2πr

μo=4π×10^-7 H/m

The force is attractive if the currents are in the same direction, repulsive if they are in opposite directions.

F/l = μoi1i2/2πr

F/0.3=4π×10^-7×2²/2π•0.005

F/0.3=1.6×10^-4

Cross multiply

F=1.6×10^-4×0.3

F=4.8×10^-5N

3 0
3 years ago
A driver in a car traveling at a speed of 21.8m/s sees a cat 101 m away on the road. How long will it take for the car to accele
kobusy [5.1K]
The acceleration of the car will be needed in order to calculate the time. It is important to consider that the final speed is equal to zero:

v^2 = v_0^2 + 2ad\ \to\ a = \frac{-v_0^2}{2d} = -\frac{21.8^2\ m^2/s^2}{2\cdot 99\ m} = -2.4\frac{m}{s^2}

We can clear time in the speed equation:

v = v_0 + at\ \to\ t = \frac{-v_0}{a} = \frac{-21.8\ m/s}{-2.4\ m/s^2} = \bf 9.08\ s

If you find some mistake in my English, please tell me know.
3 0
3 years ago
Read 2 more answers
Suppose a car manufacturer tested its cars for front-en4 collisions by hauling them up on a crane and dropping then; from a cert
Brrunno [24]

Answer:

a

Generally from third equation of motion we have that

v^2 =  u^2 + 2a[s_i - s_f]

Here v is the final speed of the car

u is the initial speed of the car which is zero

s_i is the initial position of the car which is certain height H

s_i is the final position of the car which is zero meters (i.e the ground)

a is the acceleration due to gravity which is g

So

v^2 = 0 + 2g[H - 0]

=> v  =  \sqrt{ 2 g H}

b

H  =  9.86 \  m

Explanation:

Generally from third equation of motion we have that

v^2 =  u^2 + 2a[s_i - s_f]

Here v is the final speed of the car

u is the initial speed of the car which is zero

s_i is the initial position of the car which is certain height H

s_i is the final position of the car which is zero meters (i.e the ground)

a is the acceleration due to gravity which is g

So

v^2 = 0 + 2g[H - 0]

=> v  =  \sqrt{ 2 g H}

When v  = 50 \  km/h = \frac{50 *1000}{3600} = 13.9 \  m/s we have that

13.9  =  \sqrt{ 2 g H}

=> H  =  \frac{13.9^2}{2 *  9.8}

=> H  =  9.86 \  m

6 0
3 years ago
Find the frequency of a wave with the wavelength 3.5 m and the speed is 50 m/s. <br>​
Andru [333]

Answer:

8.57 Hz

Explanation:

From the question given above, the following data were obtained:

Wavelength (λ) = 3.5 m

Velocity (v) = 30 m/s

Frequency (f) =?

The velocity, wavelength and frequency of a wave are related according to the equation:

Velocity = wavelength × frequency

v = λ × f

With the above formula, we can simply obtain the frequency of the wave as follow:

Wavelength (λ) = 3.5 m

Velocity (v) = 30 m/s

Frequency (f) =?

v = λ × f

30 = 3.5 × f

Divide both side by 3.5

f = 30 / 3.5

f = 8.57 Hz

Thus, the frequency of the wave is 8.57 Hz

7 0
3 years ago
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