1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Pani-rosa [81]
3 years ago
14

Dana is on a train traveling at a speed of 20 km/h. Dana walks from the front of the train to the back of the train at a speed o

f 4 km/h. What is Dana’s speed relative to the ground?
Physics
1 answer:
Maslowich3 years ago
7 0

Answer:

16km/h

Explanation:

Vt=20km/h ---train speed

Vd=4km/h

Donas speed relative to ground is:

Vrd=Vt-Vd

Donas is moving in opposite direction of train .

Vrd=20km/h-4km/h

Vrd=16km/h

You might be interested in
The following represents a mass attached to a spring oscillating in simple harmonic motion. X(t) = 4.0 cos(3.0t +0.10) units of
kolbaska11 [484]

Answer:

a) A = 4.0 m , b)   w = 3.0 rad / s , c)  f = 0.477 Hz , d) T = 20.94 s

Explanation:

The equation that describes the oscillatory motion is

          x = A cos (wt + fi)

In the exercise we are told that the expression is

          x = 4.0 cos (3.0 t + 0.10)

let's answer the different questions

a) the amplitude is

         A = 4.0 m

b) the frequency or angular velocity

         w = 3.0 rad / s

c) angular velocity and frequency are related

          w = 2π f

           f = w / 2π

           f = 3 / 2π

           f = 0.477 Hz

d) the period

frequency and period are related

           T = 1 / f

           T = 1 / 0.477

           T = 20.94 s

e) the phase constant

          Ф = 0.10 rad

f) velocity is defined by

          v = dx / dt

         

         v = - A w sin (wt + Ф)

speed is maximum when sine is + -1

         v = A w

          v = 4 3

          v = 12 m / s

g) the angular velocity is

          w² = k / m

          k = m w²

          k = 1.2 3²

          k = 10.8 N / m

h) the total energy of the oscillator is

          Em = ½ k A²

           Em = ½ 10.8 4²

          Em = 43.2 J

i) the potential energy is

           Ke = ½ k x²

for t = 0 x = 4 cos (0 + 0.1)

               x = 3.98 m

j) kinetic energy

           K = ½ m v²

for t = 00.1 ²

    v = A w sin 0.10

    v = 4 3 sin 0.10

    v = 1.98 m / s

3 0
2 years ago
A billiard ball strikes and rebounds from the cushion of a pool table perpendicularly. The mass of the ball is 0.38 kg The ball
xxTIMURxx [149]

Answer:

Force is 432.94 N along the rebound direction of ball.

Explanation:

Force is rate of change of momentum.

\texttt{Force}=\frac{\texttt{Final momentum-Initial momentum}}{\texttt{Time}}

Final momentum = 0.38 x -1.70 = -0.646 kgm/s

Initial momentum = 0.38 x 2.20 = 0.836 kgm/s

Change in momentum = -0.646 - 0.836 = -1.472 kgm/s

Time = 3.40 x 10⁻³ s

\texttt{Force}=\frac{\texttt{Final momentum-Initial momentum}}{\texttt{Time}}=\frac{-1.472}{3.40\times 10^{-3}}\\\\\texttt{Force}=-432.94N

Force is 432.94 N along the rebound direction of ball.

7 0
3 years ago
Answer the following. (a) What is the surface temperature of Betelgeuse, a red giant star in the constellation of Orion, which r
bagirrra123 [75]

Answer:

(a) T = 2987.6 k

(b) T = 19986.2 k

Explanation:

The temperature of a star in terms of peak wavelength can be given by Wein's Displacement Law, which is as follows:

T = \frac{0.2898\ x\ 10^{-2}\ m.k}{\lambda_{max}}

where,

T = Radiated surface temperature

\lambda_{max} = peak wavelength

(a)

here,

\lambda_{max} = 970 nm = 9.7 x 10⁻⁷ m

Therefore,

T = \frac{0.2898\ x\ 10^{-2}\ m.k}{9.7\ x\ 10^{-7}\ m}

<u>T = 2987.6 k</u>

(b)

here,

\lambda_{max} = 145 nm = 1.45 x 10⁻⁷ m

Therefore,

T = \frac{0.2898\ x\ 10^{-2}\ m.k}{1.45\ x\ 10^{-7}\ m}

<u>T = 19986.2 k</u>

6 0
2 years ago
A converging lens of focal length 20 cm is placed in contact with, and to the left of, a diverging lens of focal length 30 cm. I
scZoUnD [109]

Answer:

Magnification will be equal to 3

Explanation:

We have given focal length of the converging lens F_1=20cm

Focal length of the diverging lens F_2=30cm

Object is placed 40 cm to the length of the converging lens d = 40 cm

Combination of the focal length will be equal to

\frac{1}{F}=\frac{1}{F_1}+\frac{1}{F_2}

\frac{1}{F}=\frac{1}{20}+\frac{1}{-30}=\frac{1}{20}-\frac{1}{30}=\frac{1}{60}

F = 60 cm

So combination of the focal length will be 60 cm

Magnification is given by

M=\frac{F}{F-d}=\frac{60}{60-40}=3

So magnification will be equal to 3

3 0
3 years ago
What is another name for kidney stones?
Naddika [18.5K]

Another (slightly more technical) name for kidney stones is "renal calculus".

I know this because we have met many times, and we are old friends.


8 0
3 years ago
Read 2 more answers
Other questions:
  • 1. How much energy would be required to melt 450 grams of ice at 0°C?
    12·1 answer
  • Turning a vector to a scalar is possible ???​
    5·1 answer
  • A 1.0 kg mass is attached to the end of a vertical ideal spring with a force constant of 400 N/m. The mass is set in simple harm
    8·1 answer
  • What is the specific heat of an unknown substance if 2000 J of energy are required to raise the temperature of 4 grams of the su
    10·1 answer
  • When using water displacement to measure the volume of an irregularly shaped solid, like a rock, which of the following would be
    10·2 answers
  • Distinguish between resultant and equilibrant forces<br><br><br>​
    5·1 answer
  • You will now use Graphical Analysis to calculate the slope of the line. Choose Analyze from the menu. Select Automatic Curve Fit
    11·1 answer
  • Currently, the Sun is thought to be located in the galactic _____________ about ____________ the center of the galaxy.
    12·1 answer
  • Disordered eating is often __________.
    6·2 answers
  • What is the force of gravity between two 50.0kg masses that are separated by 0.300m?3.71x10-8N5.59x10-7N2.78x104N1.85x10-6N
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!