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
gulaghasi [49]
3 years ago
12

Alex is standing still and throws a football with a speed of 10 m/s to his friend, who is also standing still. The two friends a

re standing 5 meters apart. Which describes how each person observes the speed of the football?
Physics
2 answers:
Phantasy [73]3 years ago
7 0

The question is incomplete. It comes with a set of answer choices.


These are the answer choices:


Alex observes it as 10 m/s, and his friend observes it as less than 10 m/s.


Alex observes it as less than 10 m/s, and his friend observes it as 10 m/s.


Both Alex and his friend observe it as 10 m/s.


Both Alex and his friend observe it as less than 10 m/s.



Answer: Both Alex and his friend observe it as 10 m/s.


Justification:


1) The speed is relative to the frame of reference.


2) It is said that the both Alex and his friend are standing still.


3) Then, the speed they both see is the same, 10 m/s, respect the Earth (where they are standing still).


Of course, Alex is watching the ball moving away and his friend is seing it approaching, but it is not relevant for the question, as it deals with the speed which is only about magnitude, not direction.

Readme [11.4K]3 years ago
6 0

Answer:

c on edge

Explanation:

You might be interested in
Which of the following is an example of a double replacement reaction?
ziro4ka [17]
B because you can see the elements being swapped by the other elements on both sides of the equation, please mark me as Brainlliest
3 0
3 years ago
Read 2 more answers
Which is belief held by sociologists who work from a social-conflict perspective
Ksju [112]
Some social patterns are helpful, while others are harmful.
7 0
3 years ago
Read 2 more answers
shows a conical pendulum, in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at const
Contact [7]

Answer:

a) T=0.40 N

b) T=1.9 s

Explanation:

Let's find the radius of the circumference first. We know that bob follows a circular path of circumference 0.94 m, it means that the perimeter is 0.94 m.

The perimeter of a circunference is:

P=2\pi r=0.94

r=\frac{0.94}{2\pi}=0.15 m

Now, we need to find the angle of the pendulum from vertical.

tan(\alpha)=\frac{r}{L}=\frac{0.15}{0.90}=0.17

\alpha=9.44 ^{\circ}

Let's apply Newton's second law to find the tension.

\sum F=ma_{c}=m\omega^{2}r

We use centripetal acceleration here, because we have a circular motion.

The vertical equation of motion will be:

Tcos(\alpha)=mg (1)

The horizontal equation of motion will be:

Tsin(\alpha)=m\omega^{2}r (2)

a) We can find T usinf the equation (1):

T=\frac {mg}{cos(\alpha)}=\frac{0.04*9.81}{cos(9.44)}=0.40 N

We can find the angular velocity (ω) from the equation (2):

\omega=\sqrt{\frac{Tsin(\alpha)}{mr}}=3.31 rad/s

b) We know that the period is T=2π/ω, therefore:

T=\frac{2\pi}{\omega}=\frac{2\pi}{3.31}=1.9 s

I hope it helps you!

8 0
2 years ago
If you pour different liquids into a graduated cylinder, which layer would be at the bottom?
klasskru [66]

the one that is more dense!

5 0
3 years ago
Anyone want to help a brother out
s344n2d4d5 [400]
I would say B but I’m not 100%
5 0
3 years ago
Other questions:
  • How do mass and speed affect kinetic energy?
    12·1 answer
  • PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!
    11·2 answers
  • What is the mass of a baseball that has a kinetic energy of 100 J and travel at 5 m/s
    14·2 answers
  • Which one of the following situations is not possible?
    6·1 answer
  • Someone help me pls
    15·1 answer
  • Take the distance between the Earth and the Sun to be 149,500,000,000 m. Calculate the velocity of the Earth in its
    15·1 answer
  • What does a notational analyst do
    11·1 answer
  • SOMEBODY PLEASE HELP!! 20 PTS!!!
    13·2 answers
  • Electric field shows the strength and what of an electric field
    14·2 answers
  • EVERYONE BE AWARE IF YOU GET SENT SOMETHING LIKE THIS (Answer is in the photo. I can only upload it to a file hosting service. l
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!