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
andrey2020 [161]
3 years ago
8

I NEED HELP!!!!! PLEASE ANSWER! FIRST CORRECT ANSWER WILL GET BRAINLIEST AND I WILL FOLLOW YOU!

Physics
1 answer:
Naily [24]3 years ago
6 0

Average speed = (total distance) / (time to cover the distance)

We know:

    Average speed = 65 km/hr
    Total distance = 1,000 km 
    Time to cover it = (Driving Time) + 4 hours.

so we can write:

          65 km/hr  =  (1,000 km) / (Driving Time + 4hr)

          (I'm going to start calling the driving time 'DT'.
           Notice that DT is a number with the units of 'hours'.)

Multiply each side by    (DT + 4hr)

           (65 km/hr) (DT + 4hr)  =  1,000 km   

Eliminate parentheses on the left side:

           (65·DT km  +  260 km)  =  1,000 km

Subtract  260km  from each side:

              65·DT km          =    740 km

Divide each side by 65 :

                DT   =   11.38 hours .

DT (Driving Time) is the time you spent actually driving.
You had to cover the complete 1,000 km in that time.
So while you were driving, you had to do it at a speed of

                  1,000 km / 11.38 hrs  =  87.8 km/hr .
__________________________________________

As long as we're already totally bored by this question,
let's work on it some more, and check my answer:

... Driving for 11.38 hours at a speed of 87.8 km/hr, you cover

                     (11.38 hr) x (87.8 km/hr)  =  999.164 km  (close enough to 1,000) .

So far, so good.  The distance is taken care of.

With the 4-hour stop, the total trip takes 4 more hours = 15.38 hours.
So the average speed is

                     (1,000 km) / (15.38 hr)  =   65.02 km/hr

                                                                Close enough to 65 km/hr.  yay !

You might be interested in
Which of the following diagrams shows the path of deep water currents in the ocean?
Whitepunk [10]
I hope this helps. ^-^

6 0
4 years ago
How many mm are in a micro-m?
Dahasolnce [82]

For this case we have that by definition, a micrometer is equivalent to a thousandth of a millimeter, that is, 0.001 millimeters.

Then, in other words, we have 0.001 millimeters in a micrometer.

Answer:

In a micrometer there are 0.001 millimeters.

4 0
3 years ago
Where is the potential energy equal to zero?
s2008m [1.1K]

Answer:

im sure your already past this but it's E.

Explanation:

This is because in this case potential energy is linear to height, which means that the higher the more potential energy.

4 0
3 years ago
In general, if the temperature of a chemical reaction is increased, the reaction rateA. IncreasesB. decreasesC. remains the same
In-s [12.5K]
A. Increases

I would assume this to be the answer because heat is another form of energy. If there is more energy the molecules will become more active. This makes A the most logical answer.
6 0
3 years ago
A book falling to the floor is best described by: law one, law two, law three, or all three laws?
Law Incorporation [45]

The book falling to the floor is described by Newton's second law and Newton's third law

Explanation:

Newton's first law of motion states that:

"An object moving at constant velocity (or at rest) keeps moving at constant velocity (or will stay at rest) unless acted upon unbalanced, external forces"

For a book falling to the floor, there is an unbalanced force acting on it (the  force of gravity): therefore, we cannot apply Newton's first law.

Newton's second law of motion states that:

"The net force acting on an object is equal to the product between the object's mass, m, and its acceleration, a"

Mathematically:

F=ma

For the book falling to the floor, F is the force of gravity; therefore, we can apply Newton's second law, and in this case it tells us that the book has a non-zero acceleration during its fall.

In particular, the force of gravity is F=mg (where g is the acceleration due to gravity), so the acceleration of the book is

mg=ma\\a=g=9.8 m/s^2

Newton's third law of motion states that:

"When an object A exerts a force (action force) on an object B, then object B exerts an equal and opposite  force (reaction force) on object A".

In this case, the Earth is exerting a  force (the force of gravity) on the book during its fall: therefore, the book is also exerting a equal and opposite force (reaction force) on the Earth.

Learn more about Newton laws of motion:

brainly.com/question/3820012

brainly.com/question/11411375

#LearnwithBrainly

4 0
3 years ago
Other questions:
  • Which of the following best describes a noncontact force
    9·1 answer
  • Potential difference is measured in units called
    7·2 answers
  • When two atoms share electrons the bond is ______
    5·2 answers
  • A white dwarf is:______.
    5·1 answer
  • All of the following except ______ were part of RCA. A. Westinghouse B. Columbia Broadcasting System C. United Fruit Company D.
    9·1 answer
  • Often in Physics we will show a frame of reference as a
    15·1 answer
  • A ladder rests against a vertical wall at a point 12 feet from the floor. The angle formed by the ladder and the floor is 63°. C
    9·1 answer
  • A system gains 1500 J of heat, while the internal energy of the system increases by 4500 J and the volume decreases by . Assume
    9·1 answer
  • What's a good way to determine the net force of something
    9·1 answer
  • So this helicopter pilot dropped me in the middle of an absolutely smooth frictionless
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!