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
zhenek [66]
4 years ago
6

A stone thrown off a bridge at 20 m above a river has an initial velocity of 12 m/s at an angle of 45° above the horizontal. Wha

t is the range of the stone? At what velocity does the stone strike the water?
Physics
2 answers:
denis-greek [22]4 years ago
8 0

Answer:

a) x=26m

b) v_{y}=-21.5m/s

Explanation:

From the exercise we know initial velocity, initial height

y_{o}=20m

v_{o} =12m/s \beta =45º

a) The range of the stone is defined by how far does it goes. From the theory of <u><em>free falling objects</em></u>, we have:

y=y_{o}+v_{oy}t+\frac{1}{2}gt^{2}

The stone strike the water at y=0

0=20+12sin(45)t-\frac{1}{2}(9.8)t^{2}

Solving for t, using the quadratic formula

t=-1.33s or t=3.06s

Since time can't be negative, the answer is t=3.06s

Now, we can calculate the <u>range of the stone</u>

x=v_{o}t=(12cos(45))m/s(3.06s)=26m

b) We can calculate the <u>velocity</u> were the stone strike the water using the following formula  

v_{y}=v_{oy}+gt=12sin(45)m/s-(9.8m/s^{2})(3.06s)=-21.5m/s

The negative sign indicates that the stone is going down

alisha [4.7K]4 years ago
4 0

Answer:

(a) x= 26m

(b) vf= 23.15m/s  

Explanation:

Given data

h=20m

Ɵ=45°

to find

(a) range of stone=x=?

(b) velocity=vf=?

Solution

For part (a)

You need to solve for time first using

yf = yi + visinƟt + 1/2gt^2

0 = 20m + 12sin45t + 1/2(-9.8)t^2

and use the quadratic equation to solve for t

t = 3.064 sec

To solve for the distance traveled use

x = xi + vicosƟt + 1/2at^2 there is no acceleration in the x direction so that cancels

x = 12cos(45)(3.064)

x= 26m

For part(b)

For b I'm not sure if you what direction you want the final velocity in the x, y, or the direction its traveling so I'll just give all 3.

Theres no change in the velocity in the x direction so its just vfx = vixcosƟ = 12cos45 = 8.49m/s

For the y direction its vfy^2 = viy^2 + 2g(Δy)

vfy = sqrt((12sin(45))^2 + 2(-9.8)(0-20m)) = 21.54m/s

The velocity the direction the stone is traveling is vf = sqrt(vx^2 + vy^2) = sqrt(8.49^2 + 21.54^2)

vf= 23.15m/s

You might be interested in
The displacement of a wave traveling in the positive x-direction is y(x, t)|= (3.5 cm)cos(2.7x − 92t), where x is in m and t is
zubka84 [21]

Answer

Given,

y(x, t) = (3.5 cm) cos(2.7 x − 92 t)

comparing the given equation with general equation

y(x,t) = A cos(k x - ω t)

 A = 3.5 cm  , k = 2.7 rad/m    , ω = 92 rad/s

we know,

a) ω =2πf

   f = 92/ 2π

   f = 14.64 Hz

b) Wavelength of the wave

 we now, k = 2π/λ

      2π/λ = 2.7

      λ = 2 π/2.7

      λ = 2.33 m

c) Speed of wave

     v = ν λ

     v = 14.64 x 2.33

     v = 34.11 m/s

5 0
4 years ago
Which of these is an example of a physical change? Question options: wood decaying iron melting paper burning steel rusting
marin [14]
Im pretty sure burning paper

its either that or melting iron but im 90 percent sure its paper burning
4 0
3 years ago
Renewable resources need to be conserved because
creativ13 [48]

Answer:

(A) We are using them faster than they are replenished by nature

4 0
3 years ago
Explain how fluids exert pressure
Veseljchak [2.6K]
In a fluid, all the forces exerted by the individual particles combine to make up the pressure exerted by the fluid 
Due to fundamental nature of fluids, a fluid cannot remain at rest under the presence of shear stress. However, fluids can exert pressure normal to any contacting surface. If a point in the fluid is thought of as a small cube, then it follows from the principles of equilibrium that the pressure on every side of this unit of fluid must be equal. but if this were not a case, the fluid would move in the directions of the resulting force, So the pressure on a fluid at rest is isotropic. 
Hope This Helps :D  <span />
4 0
3 years ago
What is the kinetic energy of a ball that has a mass of 3kg and Is<br> moving at 5m/s?
Arada [10]

Answer:

E kin = 1/2 • m • v^2

E kin: kinetic energy

m: mass

v: velocity

Explanation:

6 0
3 years ago
Other questions:
  • The Earth’s internal __________ source provides the energy for our dynamic planet, providing it with the driving force for on-go
    7·1 answer
  • Which of the following statements about iron filings placed upon glass resting on top of a bar magnet is false?
    11·1 answer
  • How do hurricanes differ from tornadoes?
    12·1 answer
  • As you sit outside, the sound of a siren becomes lower in pitch. Is the emergency vehicle moving away from or towards you? expla
    8·1 answer
  • A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s. The vector sum of all the forces acting on this crate
    5·1 answer
  • How did the invention of movable type change society?
    10·1 answer
  • Doing work alawyas means blank energy​
    11·1 answer
  • What is the kinetic energy of a 6 kg and 2 m long thin rod that rotates with angular velocity of 10 rad/s
    7·1 answer
  • What is the current in a circuit if the charge passing each point is 10current <br>in 2s​
    7·1 answer
  • Most people can throw a baseball farther than a bowling ball, and most people would find it less painful to catch a flying baseb
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!