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 these BEST describes the term ecliptic? A. the circle where "Earth meets the sky" B. the change in azimuth and altitude
jeyben [28]
I'll say B ....hope that helps...
4 0
3 years ago
Read 2 more answers
Weight is measured in units called
Aleksandr-060686 [28]
Pounds

If you are talking about the unit of measurement for weight is that of force it would be Newtons.
8 0
3 years ago
The sun produces energy by forming in its core
Shalnov [3]
The Sun <span>produces energy by forming "Helium" in its core by the process of "Nuclear fusion"

Hope this helps!</span>
7 0
3 years ago
0.A 20-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s. What is the kinetic
Fiesta28 [93]

Answer:

KE = 0.162 KJ

Explanation:

given,

mass of bullet (m)= 20 g = 0.02 Kg

speed of the bullet (u)= 1000 m/s

mass of block(M) = 1 Kg

velocity of bullet after collision (v)= 100 m/s

kinetic energy = ?

using conservation of momentum

m u = m v + M V

0.02 x 1000 = 0.02 x 100 + 1 x V

20 = 2 + V

V = 18 m/s

now,

Kinetic energy of the block

KE = \dfrac{1}{2}mv^2

KE = \dfrac{1}{2}\times 1 \times 18^2

KE = 162 J

KE = 0.162 KJ

4 0
3 years ago
An elastic rope is tied securely to a wall. An upward-displaced pulse is introduced into the rope. The pulse travels through the
Natasha2012 [34]

Answer:

Inverted (displaced downwards)

Explanation:

The pulse becomes INVERTED upon reflecting off the boundary with the wall. That is, an upward-displaced pulse will reflect off the end and return with a downward displacement. This inversion behavior will always be observed when the end of the medium is fixed, like this wall in this instance. This INVERSION BEHAVIOR can also be observed when the medium is connected to another more heavy or more dense medium. And in this case, when the pulse reaches the end of the medium, a portion of the pulse will reflect off the end and return with an inverted displacement. The heavier medium acts like a fixed end to cause the pulse to be inverted.

Summary: a pulse reaching the end of a medium becomes inverted whenever it either:

i. reflects off a fixed end,

ii. is moving in a less dense medium and reflects off a more dense medium.

3 0
3 years ago
Other questions:
  • What are the possible values of n and ml for an electron in a 3d orbital?
    10·1 answer
  • What is the concentration of OH– ions at a pH = 6?
    5·1 answer
  • Which is a true statement about a series circuit?
    15·1 answer
  • Two rods are identical, except that one is brass (Y = 9.0 × 1010 N/m2) and one is tungsten (Y = 3.6 × 1011 N/m2). A force causes
    11·1 answer
  • A square sheet of rubber has sides that are 20 cm long. What is the area of the square of rubber in cm squared?
    9·1 answer
  • When does the most significant drop in physical activity typically occur in people's lives?
    6·1 answer
  • 2225.6 grams =________ ft
    5·1 answer
  • Why do astronomers hypothesize that a massive black hole lies at the center of m87?
    12·1 answer
  • 2. A mass-spring system oscillates with a frequency of 20 Hz. What is the period?
    15·1 answer
  • How long does it take to shut down a nuclear reactor?.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!