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
frutty [35]
3 years ago
5

If humans originated in Africa and migrated to other parts of the world some time would be required for this to occur.At the mod

est rate of one kilometer per year, how many centuries would it take for humans originated in Africa to travel to China, some 10,000 kilometers away? ​
Physics
1 answer:
Thepotemich [5.8K]3 years ago
7 0

Answer:

100 years

Explanation:

10,000 divided by 100 equals 100

You might be interested in
A submarine is 2.84 102 m horizontally from shore and 1.00 102 m beneath the surface of the water. A laser beam is sent from the
xxMikexx [17]

Answer:

468 m

Explanation:

So the building and the point where the laser hit the water surface make a right triangle. Let's call this triangle ABC where A is at the base of the building, B is at the top of the building, and C is where the laser hits the water surface. Similarly, the submarine, the projected submarine on the surface and the point where the laser hit the surface makes a another right triangle CDE. Let D be the submarine and E is the other point.

The length CE is length AE - length AC = 284 - 234 = 50 m

We can calculate the angle ECD:

tan(\hat{ECD}) = \frac{ED}{EC} = \frac{100}{50} = 2

\hat{ECD} = tan^{-1} 2 = 63.43^o

This is also the angle ACB, so we can find the length AB:

tan(\hat{ACB}) = \frac{AB}{AC} = \frac{AB}{234}

2 = \frac{AB}{234}

AB = 2*234 = 468 m

So the height of the building is 468m

5 0
4 years ago
7. A car moving at 10m/s (about 22.4 mph) crashes into a barrier and stops in 0.25 m.
Galina-37 [17]

Answer:

a) 0.05s

b) 4000N

Explanation:

a)When car is stopped its final velocity become zero

U- 10 m/s

V- 0 m/s

S - 0.25 m

t -?

S = (v+u)*t/2

0.25 =(10+0)*t/2

t = 0.05s

b) If we happened to calculate the avarage force we have to consider about acceleration

V= 0

U = 10

t = 0.05 s

a =?

V = U + at

0 = 10 -a * 0.05

a = 200 m/s2

F = m *a

= 20 * 200

= 4000N

6 0
3 years ago
Mary cycled at an average speed of 8 km/h. How far has she traveled if she rides for 4 hours?
Sati [7]

Answer:

Which sentence from the passage shows that the function of the river depicted here has carried through to modern times?

Explanation:

Which sentence from the passage shows that the function of the river depicted here has carried through to modern times?

4 0
3 years ago
Read 2 more answers
A sound wave is passing by a student 250 times every second. What is the frequency of the sound wave?
inysia [295]
My answer i believe is simply 250 Hz, because sounds or vibrations travel in 1 cycle/second, meaning the number of cycles, in your case 250, divided by the time,1 second, will ultimately be 250 Hertz.  For every Cycle/second it will equal 1 Hz, so 250/1 = 250Hz
7 0
3 years ago
Read 2 more answers
A 50-kg person stands 1.5 m away from one end of a uniform 6.0-m-long scaffold of mass 70.0 kg.
babymother [125]

Answer

given,

mass of the person, m = 50 Kg

length of scaffold = 6 m

mass of scaffold, M= 70 Kg

distance of person standing from one end = 1.5 m

Tension in the vertical rope = ?

now equating all the vertical forces acting in the system.

T₁ + T₂ = m g + M g

T₁ + T₂ = 50 x 9.8  + 70 x 9.8

T₁ + T₂ = 1176...........(1)

system is equilibrium so, the moment along the system will also be zero.

taking moment about rope with tension T₂.

now,

T₁ x 6 - mg x (6-1.5) - M g x 3 = 0

'3 m' is used because the weight of the scaffold pass through center of gravity.

6 T₁ = 50 x 9.8 x 4.5 + 70 x 9.8 x 3

6 T₁ = 4263

    T₁ = 710.5 N

from equation (1)

T₂ = 1176 - 710.5

 T₂ = 465.5 N

hence, T₁ = 710.5 N and T₂ = 465.5 N

4 0
4 years ago
Other questions:
  • An electron with a speed of 0.965 c is emitted by a supernova, where c is the speed of light. What is the magnitude of the momen
    6·2 answers
  • What is the technical name for the animal kingdom
    6·1 answer
  • How many feet are there in a meter?
    5·2 answers
  • A uniform brick of length 25 m is placed over
    11·1 answer
  • A cannon of mass 6.43 x 103 kg is rigidly bolted to the earth so it can recoil only by a negligible amount. The cannon fires a 7
    8·1 answer
  • A 50 Ω resistor in a circuit has a current flowing through it of 2.0 A. What is the power dissipated by the resistor?
    5·1 answer
  • What happens when you pay bills using a computer
    7·2 answers
  • 1) Manipulate is to measure as
    5·1 answer
  • Velocity ratio of a machine is 4 what does it mean​
    12·1 answer
  • The range of diameters and luminosities displayed by elliptical galaxies is ____.
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!