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
steposvetlana [31]
3 years ago
8

A car moves with a speed of 72 km/h for 15 minutes and then with a speed of 80 km/h for the next 12 minutes. The total distance

covered by the car is:
Physics
2 answers:
sukhopar [10]3 years ago
8 0

Answer:

The total distance covered by the car is 3,810.08 m

Explanation:

Given;

initial speed of the car, u = 72 km/hr = 20 m/s

initial time, t₁ = 15 minutes = 900 s

final speed of the car, v = 80 km/hr = 22.22 m/s

final time, t₂ = 12 minutes = 720 s

The acceleration of the car is given as;

a = \frac{v-u}{t_2 -t_1} \\\\a = \frac{22.22-20}{900-720}\\\\a = 0.0123 \ m/s^2

The total distance covered by the car is given as;

v² = u² + 2as

where;

s is the total distance covered by the car

22.22² = 20² + 2(0.0123)s

22.22²  - 20² = 2(0.0123)s

93.728 = 0.0246s

s = 93.728 / 0.0246

s = 3,810.08 m

Therefore, the total distance covered by the car is 3,810.08 m

stiv31 [10]3 years ago
8 0

Answer:

34 km

Explanation:

Remark

You are dealing with distance not direction. So you just figure out the two parts separately and add.

15 minutes

t = 15 minutes * 1 hour / 60 minutes = 0.25 hours.

r = 72 km / hr

d = 72 km / hr * 0.25 hours

d = 18 km

12 minutes

t = 12 minutes * 1 hour/ 60 minutes = 0.2 hours

r = 80 km/hour

d = 80 * 0.2 = 16 km

Total distance

d = d1 + d2

d = 18 + 16 = 34 km

You might be interested in
An insulated rigid tank initially contains 1.4-kg saturated liquid water and water vapor at 200°C. At this state, 25 percent of
Elan Coil [88]

Solution:

Mass of liquid water and water vapor in the insulated tank initially = 1.4 kg

Temperature = 200 °C

And 25% of the volume by liquid water is steam.

State 1

$m=\frac{V}{v}$

$m=m_f+m_g$

$1.4=\frac{0.25V}{v_f}+\frac{0.75V}{v_g}$

$1.4=\frac{0.25V}{1.1565 \times 10^{-3}}+\frac{0.75V}{0.1274}$       (taking the value of $v_g$ and $v_g$ at 200°C  )

$V=6.304 \times 10^{-3}$

Now quality of vapor

$x=\frac{m_g}{m}$

  $=3.377 \times 10^{-3}$

Internal energy at state 1 can be found out by

$u_1=u_f+xu_{fg}$

    $=850.65+3.377\times10^{-3}\times 1744.65$

    = 856.54 kJ/kg

After heating with the resistor for 20 minutes, at state 2, the tank contains saturated water vapor $v_2=v_g \text { and }\ x=1$

Tank is rigid, so volume of tank is constant.

$v_g=v_2=\frac{V}{m}$

$v_g=\frac{6.304\times 10^{-3}}{1.4}$

$v_g=4.502 \times 10^{-3} \ m^3 /kg$

Now interpolate the value to get temperature at state 2 with specific volume value to get final temperature

$T_2=360+(374.14-360)\left(\frac{0.004502-0.006945}{0.003155-0.006945}\right)$

   = 369.11° C

Internal energy at state 2

$u_2=2154.9 \ kJ/kg$

Now power rating of the resistor

$P=\frac{m(u_2-u_1)}{t}$

$P=\frac{1.4(2154.9-856.54)}{20 \times 60}$

  = 1.51 kW

6 0
3 years ago
A boat takes 3.0 hours to travel 50 km down a river, then 5.4 hours to return. Determine the speed of the water in the river.
Nutka1998 [239]

Answer:

3.7 km/h

Explanation:

Let's call v the proper speed of the boat and v' the speed of the water in the river.

When the boat travels in the direction of the current, the speed of the boat is:

v + v'

And it covers 50 km in 3 h, so we can write

v+v' = \frac{50 km}{3 h}=16.7 km/h (1)

When the boat travels in the opposite direction, the speed of the boat is

v - v'

And it covers 50 km in 5.4 h, so

v-v'=\frac{50 km}{5.4 h}=9.3 km/h (2)

So we have a system of two equations: by solving them simultaneously, we find the value of v and v':

v+v'=16.7 \\v-v'=9.3

Subtracting the second equation from the first one we get:

(v+v')-(v-v')=16.7-9.3\\2v'=7.4\\v'=3.7

So, the speed of the water is 3.7 km/h.


5 0
3 years ago
How does kinect energy affect the stopping distance of a vehicle traveling at 30 mph compared to the same vehicle traveling at 6
mote1985 [20]

If it is the same vehicle, then the 60mph vehicle has more kinetic energy since it is moving faster. Therefore, it requires more energy to stop, and if it is the same car with the same beak system, the braking distance of the 30mph car will be significantly shorter than the 60mph car.



8 0
3 years ago
What is it called when data are arranged in rows and columns?
Tpy6a [65]

Answer:

C. Table

<h2>What is a Database table?</h2>

A organized collection of records is called a database table. The main key that uniquely identifies each row in the table. Since no two rows may have the same instantaneous value thanks to a unique key, it is simple to choose a row by its main key. A table can also contain several columns, each of which can hold a distinct kind of data. The information stored is verified using the column name and data type.  

The table name is the linguistic component of a database table. It can represent expressions or variable items, and it must be typed exactly. Square brackets denote a need for the item, whereas curly braces denote an optional element. An alternate choice is indicated by a vertical bar. A main key is a single field, and a secondary key might be a combination of many fields. This kind of information is crucial.

Any field in the data table can be referenced by the secondary key. A database's data field may be a string, a number, a date, or a time. A table's first field should always be the main key, followed by any foreign keys. Actual data should never be present in a primary key. Since the immediate key value is derived from external sources, it is crucial to use it properly. Otherwise, data input mistakes may occur.

The information kept in the database table is referred to as a secondary key. This kind is a primary key, which implies it is a secondary key. A primary key can be used as an alternate key to distinguish between different records in a table and to uniquely identify a record inside a database. Multiple fields that can be either main or alternative make up a composite key.

Depending on the type of data being stored and its intended use, a database table may have a single row or several. The main key determines the number of rows, which might be 50 or more. A secondary key can be used to establish connections between various tables and to distinguish between various data types in a database. A data table also includes a secondary key, which is essential for data retrieval and is separate from the primary key.

You can have local or global database tables. The two types of tables differ in terms of names, availability, and visibility. A global table is accessible to all users and may be utilized by any other user, while a local table is only visible to the present user. It is distinct from a typical table and requires more effort to build than a straightforward one does. Its main function is to maintain a database and store data.

Rows in a database table can be of any size. A table's rows can include any number of columns. A database table's rows can be arranged in any way. The number of rows on a data page might range from one to thousands. Each row may consist of a clustered index, a row, or both. A list of columns may also be present in a row. A clustered index can only contain information in a particular sequence.

A table can be set up in  two different ways. The information-containing row of data is its main key. The data column that contains the values for a row is known as a secondary key. A database that employs rows is the third form of table. Multiple primary keys are possible for a data row, and a secondary key is a secondary key that refers to a row column. A database will have a foreign key if it is formed with a single primary key.

There is no limit to the amount of rows and columns in a database table. Up to 1,024 rows are allowed in a typical user-defined table. The server's storage capacity determines how many rows can fit in a database table. A table can have characteristics added to it in addition to the column and row. A restriction can stop a row from having empty fields. The connection between two tables can be established via an important control.

8 0
2 years ago
Read 2 more answers
CAN SOME ONE TALK TO ME PLZ ASAP IM GOING THROUGH A BAD TIME
ss7ja [257]

Hey! How's it going? If you need anything, feel free to send me a friend request and message me.

Don't worry if things get wrong, they will surely get better, if not, I'm here to talk to you. :)

7 0
3 years ago
Other questions:
  • Which is true about inelastic collisions: a. An inelastic collision does not obey conservation of energy. b. An inelastic collis
    8·1 answer
  • What type of galaxy has mostly old stars, without a lot of star formation?
    13·2 answers
  • What are the 3 major uses of water? Describe each in 3-4 sentence
    5·1 answer
  • Transverse waves are sent along a 5.00-m-long string with a speed of 30.00 m/s. The string is under a tension of 10.00 N. What i
    8·1 answer
  • In hydroelectric dams, gravitational potential energy is used to produce electrical energy. What is the mass of water that must
    10·1 answer
  • In which of the following can you not find plasma
    15·1 answer
  • A pilot drops a bomb from a plane flying horizontally. Where will the plane be located when the bomb hits the ground
    8·1 answer
  • Use a variation model to solve for the unknown value. Use as the constant of variation. The stopping distance of a car is direct
    8·1 answer
  • Please help!!!!!!!!!
    9·1 answer
  • Please help<br><br>why does 45° produce a max. range?​
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!