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trasher [3.6K]
3 years ago
7

Why do other stars look much dimmer than the sun?

Physics
1 answer:
brilliants [131]3 years ago
4 0
A star's brightness also depends on its proximity to us. The more distant an object is, the dimmer it appears. Therefore, if two stars have the same level of brightness, but one is farther away, the closer star will appear brighter than the more distant star - even though they are equally bright!
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Karl measures the current through a resistor. What else will he need to measure in order to work out its resistance?
Shkiper50 [21]

Answer:

The voltage (V)

Explanation:

Ohms, in his law, has explained the relationship between current, resistance and voltage.

Ohm's law, which states that the voltage passing through a resistor is directly proportional to both the current and the resistance of the resistor, has the following equation:

V = IR

Where;

V = voltage (volts)

I = current (Amperes)

R = resistance (ohms)

According to this question, Karl measures the current, I, through a resistor. In order to calculate his resistance, R, he will need to measure the voltage, V.

7 0
3 years ago
A stationary police car emits a sound of frequency 1240 HzHz that bounces off of a car on the highway and returns with a frequen
Tju [1.3M]

Answer

given,

frequency from Police car= 1240 Hz

frequency of sound after return  = 1275 Hz

Calculating the speed of the car = ?

Using Doppler's effect formula

Frequency received by the other car

  f_1 = \dfrac{f_0(u + v)}{u}..........(1)

u is the speed of sound = 340 m/s

v is the speed of the car

Frequency of the police car received

  f_2= \dfrac{f_1(u)}{u-v}

now, inserting the value of equation (1)

  f_2= f_0\dfrac{u+v}{u-v}

  1275=1240\times \dfrac{340+v}{340-v}

  1.02822(340 - v) = 340 + v

   2.02822 v = 340 x 0.028822

   2.02822 v = 9.799

   v = 4.83 m/s

hence, the speed of the car is equal to v = 4.83 m/s

5 0
3 years ago
A car is travelling at a speed of 30 m/s. It decelerates at a rate of 12 m/s^2. Calculate the time taken for the car to come to
user100 [1]

Answer:

The answer to your question is: t = 2.5 s

Explanation:

Data

vo = 30 m/s

a = -12 m/s2

t = ?

vf = 0 m/s

Formula

vf = vo + at

Substitution

                              0 m/s = 30 + (-12)t

Solve it for t           -30 = -12t

                              t = -30 / -12

                              t =  30/12  = 15/6 = 5/2

                              t = 2.5 s                              

8 0
3 years ago
Read 2 more answers
The radius of curvature is smaller at the top than on the sides so that the downward centripetal acceleration at the top will be
kap26 [50]

Answer:

v = 14.86 m/s

Explanation:

As we know that the force equation at the top is given as

\frac{mv^2}{R} = ma

now we know that

a_c = 1.5 g

so we have

\frac{v^2}{R} = 1.5 g

v = \sqrt{1.5 Rg}

so we will have

v = \sqrt{1.5(15)(9.81)}

v = 14.86 m/s

3 0
3 years ago
A fugitive tries to hop on a freight train traveling at a constant speed of 5.0 m/s. Just as a box car passes him, the fugitive
Dima020 [189]

Answer:Given:

Initial speed of fugitive, v0 = 0 m/s

Final speed, vf = 6.1 m/s

acceleration, a = 1.4 m/s^2

Speed of train, v = 5.0 m/s

Solution:

t = (vf-v0)/a

t = (6.1-0)/1.4

t =4.36 s

Distance traveled by train, x_T =v*t

x_T =5*4.36 = 21.8 m

Distance travelled by fugitive, x_f = v0*t+1/2at^2

x_f = 0*4.36+1/2*1.4*4.36^2

x_f =13.31 m

5*t = v(t-4.36)+x_f

5*t=6.1*(t-4.36)+13.31

solve for t, we get

t = 12.08 s

The fugitive takes 12.08 s to catch up to the empty box car.

Distance traveled to reach the box car is

X_T = v*t

X_T = 5*12.08 s

X_T = 60.4 m

Explanation:

5 0
3 years ago
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