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
natta225 [31]
3 years ago
10

A projectile is fired at an upward angle of 55° from the top of a 120 m cliff with a speed of 150 m/s. What will be its speed wh

en it strikes the ground below? (USE CONSERVATION OF ENERGY and neglect air resistance.) Express your answer to three significant figures and include the appropriate units.
Physics
1 answer:
telo118 [61]3 years ago
7 0

Answer:

The speed when it strikes the ground below is V= 157.64 m/s < -56.92º .

Explanation:

V= 150m/s

α= 55º

hi= 120m

Vy= V*sinα

Vy= 122.87 m/s

Vx= V * cos α

Vx= 86.03 m/s

h= hi + Vy * t - g*t²/2

clearing t we get the total flying time of the projectile:

t(total fly)= 26.01 sec

0= Vy - g*t

clearing t we get the maximum height time:

t(max height)= 12.53 sec

to get the fall time:

t(fall)= t(total fly) - t(max height)

t(fall)= 13.48 sec

Vy'= g* t(fall)

Vy'= 132.1 m/s

V'= √(Vx² +Vy'²)

V'= 157.64 m/s

α'= tg⁻¹ (Vy'/Vx)

α'= -56.92º

You might be interested in
6. What do the key results indicate?
slega [8]

the key result indicate that how you will achieve the your goal

7 0
3 years ago
Read 2 more answers
What does -9.8 m/s mean? And what does it mean if something has a negative velocity?
a_sh-v [17]

I can't guess what -9.8 m/s means until you tell me where it came from,
or what 'm/s' means.

If perhaps it has something to do with the acceleration of gravity on Earth,
then the correct figure is ' -9.8 m/s² '.  That means that any object that
has no other force acting on it except gravity has its speed changing by
9.8 meters per second every second.  Since it's gravity doing the job,
then the object's speed is either increasing down, or decreasing up. 

If an object has negative velocity, then it's moving in the direction opposite
to the direction that you decided to call positive when you started doing the
problem.

For example, if you decide that up is positive and down is negative, and
then somebody drops a stone from the top of a tall building, then the
gravitational force on the stone is negative (pointing down), its velocity
is negative (it's falling towards down), and its acceleration is negative (its
speed towards down is getting faster and faster).  Everything is negative,
only because you decided that up is positive and down is negative.  It's
nothing to be worried about.


4 0
3 years ago
Three points A, B, and C of unknown charges are at the corners of an equilateral triangle.
nasty-shy [4]
Answer: option d. 

Q_A= \frac{1}{2} Q_B=- \frac{1}{3} Q_C

Explanation:


1) The direction of the field lines inform about the sign of the charges.

The field lines <span>extend from the positive charges to the negative charges, so you can conclude that the charge C is positve and both charge A and charge B are negative:
</span><span>
</span><span>
</span><span>Charge C: positive
</span><span>
</span><span>Charge A: negative
</span><span>
</span><span>Charge B: netative
</span>

2) The density of the lines (number of lines in a region) inform about the magnitude of the electric field.

Since the charges are at the same distance, the magnitude of the electric field informs directly about the magnitude of the force and that about the magnitude of the charges.

Since, there are the double of lines between C and B than between C and A, the magnitude of charge B is the double than the magnitud of charge A.

From the five options given (a throug e) the only that is consistent with that charges A and B have the same sign, that charge C has different sign, and that charge B is the double of charge A is:

Q_A= \frac{1}{2} Q_B=- \frac{1}{3} Q_C
3 0
3 years ago
An engineer weighs a sample of mercury (ρ = 13.6 × 103 kg/m3 ) and finds that the weight of the sample is 6.0 n. what is the sam
Amanda [17]
Given:
ρ = 13.6 x 10³ kg/m³, density of mercury
W = 6.0 N, weight of the mercury sample
g = 9.81 m/s², acceleration due to gravity.

Let V =  the volume of the sample.
Then
W = ρVg
or
V =  W/(ρg)
   = (6.0 N)/[(13.6 x 10³ kg/m³)*(9.81 m/s²)]
   = 4.4972 x 10⁻⁵ m³

Answer: The volume is 44.972 x 10⁻⁶ m³
5 0
3 years ago
While you are in a bus that moves at 100 km/h you walk from the back to the front at 10 km/h. What is your speed relative to the
aleksklad [387]

Answer: 110km/h

100+10=110km/h

Explanation:

Motion is defined as a change of position. The frame of reference is usually assumed to be at rest. If one is sitting on a bus, the road appears to be moving backwards relative to the observer. If he/she now walks to the front of the bus, he has a speed relative to the earth which is now greater than that of the bus hence the answer.

5 0
3 years ago
Other questions:
  • What is shown in the Diagram?
    13·2 answers
  • What caused rutherford to propose a revised model of the atom
    5·1 answer
  • Which physical law underlies the first law of thermodynamics?
    13·1 answer
  • Mary takes 6.0 seconds to run up a flight of stairs that is 102 meters long. If Mary's weight is 87 newtons, what power has Mary
    12·1 answer
  • What would happen if the moon’s horizontal motion sped up too much
    12·1 answer
  • Summarize the Venn diagram.
    5·1 answer
  • Help me plzzz I need answers
    14·1 answer
  • 2) If the current in any circuit reach to infinity then its resistance becomes
    9·1 answer
  • Speed of light in air is 3 x 10 m/s, determine the speed of light in the glass fibre.
    9·1 answer
  • If 400 N of force was applied to a rock and it had an acceleration of 20 ms2 , what is the mass of rock?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!