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
Juliette [100K]
4 years ago
14

Mary walked north from her home to Sheila's home, which is 4.0 kilometers away. Then she turned right and walked another 3.0 kil

ometers to the supermarket, which is 5.0 kilometers from her own home. She walked the total distance in 1.5 hours. What were her average speed and average velocity?
Physics
1 answer:
bixtya [17]4 years ago
8 0
The answer is speed: 4.7 km/h, velocity: 3.3 km/h.

Distances and time are given:
d1 =  4 km
d2 = 3 km
d3 = 5 km
t = 1.5 h

The speed can be expressed as a distance (d) divided by time (t). The average speed (s) is total distance travelled divided by time:
s = (d1 + d2)/t = (4+3)/1.5 = 7/1.5 = 4.7 km/h

The average velocity (v) is total displacement (d₁) from the starting point divided by time. Since Mary's starting point was home, and she walked to the supermarket, which is 5.0 kilometers from her own home, her displacement is 5 km:
v = d₁/t = 5/1.5 = 3.3 km/h

You might be interested in
two bumper cars at an amusement park collide together abd get stuck together. assuming that the system of the two bumper cars is
Fiesta28 [93]

The answer to this problem is M1v1-m2v2=(m1+m2)v

7 0
3 years ago
Steam enters a one-inlet, two-exit control volume at location (1) at 360°C, 100 bar, with a mass flow rate of 2 kg/s. The inlet
yaroslaw [1]

Answer:

The inlet velocity is 21.9 m/s.

The mass flow rate at reach exit is 1.7 kg/s.

Explanation:

Given that,

Mass flow rate = 2 kg/s

Diameter of inlet pipe = 5.2 cm

Fifteen percent of the flow leaves through location (2)  and the remainder leaves at (3)

The mass flow rate is

m_{2}=0.15\times2

We need to calculate the mass flow rate at reach exit

Using formula of mass

m_{3}=m_{1}-m_{2}

m_{3}=2-0.15\times2

m_{3}=1.7\ kg/s

We need to calculate the inlet velocity

Using formula of velocity

v=\dfrac{m}{\rho A}

Put the value into the formula

v=\dfrac{2}{42.868\times\dfrac{\pi}{4}\times(5.2\times10^{-2})^2}

v=21.9\ m/s

Hence, The inlet velocity is 21.9 m/s.

The mass flow rate at reach exit is 1.7 kg/s.

7 0
4 years ago
A 45-mH ideal inductor is connected in series with a 60-Ω resistor through an ideal 15-V DC power supply and an open switch. If
Salsk061 [2.6K]

Complete question:

A 45-mH ideal inductor is connected in series with a 60-Ω resistor through an ideal 15-V DC power supply and an open switch. If the switch is closed at time t = 0 s, what is the current 7.0 ms later?

Answer:

The current in the circuit 7 ms later is 0.2499 A

Explanation:

Given;

Ideal inductor, L = 45-mH

Resistor, R =  60-Ω

Ideal voltage supply, V = 15-V

Initial current at t = 0 seconds:

I₀ = V/R

I₀  = 15/60 = 0.25 A

Time constant, is given as:

T = L/R

T = (45 x 10⁻³) / (60)

T = 7.5 x 10⁻⁴ s

Change in current with respect to time, is given as;

I(t) = I_o(1-e^{-\frac{t}{T}})

Current in the circuit after 7 ms later:

t = 7 ms = 7 x 10⁻³ s

I(t) = I_o(1-e^{-\frac{t}{T}})\\\\I =0.25(1-e^{-\frac{7*10^{-3}}{7.5*10^{-4}}})\\\\I = 0.25(0.9999)\\\\I = 0.2499 \ A

Therefore, the current in the circuit 7 ms later is 0.2499 A

6 0
3 years ago
A wave has a wavelength of 13 mm and a frequency of 18 hertz. What is its speed?
labwork [276]
Velocity = Frequency x Wavelength

= 18 x 13 = 234 mm/s
4 0
3 years ago
What is the force of gravity on an 100kg person standing on the earth
Bingel [31]
I think its 980.7
because 9.807 × 100
5 0
3 years ago
Other questions:
  • A new "smart" refrigerator has been designed with sensors that send information to the manufacturer about the refrigerator's use
    15·1 answer
  • When did they start using the word "Scrubbed" for launches?
    15·1 answer
  • A 397-N wheel comes off a moving truck and rolls without slipping along a highway. At the bottom of a hill it is rotating at 25.
    10·1 answer
  • What is the SI unit for intensity?
    8·1 answer
  • A 20 kg box is being pulled across a floor by a horizontal rope. The tension in the rope is 99 Newtons. The coefficient of frict
    12·2 answers
  • In a domestic electric circuit (220.V),an electric kettle of 3kW power rating is operatedthat has a current rating of 4A. What r
    9·1 answer
  • A revolutionary war cannon, with a mass of 2260 kg, fires a 15.5 kg ball horizontally. The cannonball has a speed of 109 m/s aft
    6·1 answer
  • Plz help An X-ray technician will place a lead cloth over parts of your body when taking an X-ray to protect your cells from bei
    13·2 answers
  • Eight 7.0W Christmas tree lights are strung in series to a 110 V light source. What is the resistance of each bulb?
    7·1 answer
  • What happens at the end of most cold currents?​
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!