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
garri49 [273]
3 years ago
10

A baseball is hit that just goes over a wall that is 45.4m high. If the baseball is traveling at 46.2 m/s at an angle of 32.7° b

elow the horizontal when it crosses the wall, and if the ball was initially hit by the batter when the ball was 1m above the ground, a. What was the ball’s initial velocity (state speed and angle)
Physics
1 answer:
mario62 [17]3 years ago
5 0

Answer:

54.9 m/s at 44.9 degrees

Explanation:

If the ball has a total velocity of 46.2 m/s, at an angle of -32.7 degrees, we can decompose its speed into its horizontal and vertical components.

Vx = V * cos(a) = 46.2 * cos(-32.7) = 38.9 m/s

Vy = V * sin(a) = 46.2 * sin(-32.7) = -25 m/s

SInce there is no force on the horizontal direction (omitting air drag), we can assume constant horizontal speed.

Since a ball thrown is at free fall, only affected by gravity (omitting air drag), we can say it is affected by constant acceleration, therefore we can use

Y(t) = Y0 + Vy0 *t + 1/2 * a * t^2

We consider t=0 as the moment when the ball was hit, so in this case Y0 = 1 m

If we take the first derivative of the equation of position, we get the equation for speed

V(t) = Vy0 + a * t

We know that being t2 the moment the ball goes over the wall

V(t2) = -25 m/s

Y(t2) = 45.4 m

So:

45.4 = 1 + Vy0 * t2 + 1/2 * a * t2^2

-25 = Vy0 + a * t2

Then:

Vy0 = -25 - a * t2

So:

45.4 = 1 + (-25 - a * t2) * t2 + 1/2 * a * t2^2

0 = -44.4 - 25 * t2 - 1/2 * a * t2^2

a = -9.81 m/s^2

0 = -44.4 - 25 * t2 + 4.9 * t2^2

Solving this quadratic equation we get:

t1 = -1.39 s

t2 = 6.5 s

Since we are looking for a positive value we disregard t1.

Now we can obtain Vy0:

Vy0 = -25 + 9.81 * 6.5 = 38.76 m/s

Since horizontal speed is constant Vx0 = 38.9 m/s

By Pythagoras theorem we obtain the value of the initial speed:

V0 = \sqrt{Vx0^2 + Vy0^2} = \sqrt{38.9^2 + 38.76^2} = 54.9 m/s

The angle is in the the first quadrant because both comonents ate positive, so: 0 < a < 90

a = atan(Vy0/Vx0) = 44.9 degrees

You might be interested in
A student is trying to determine if a solution is acidic or basic. She does not have any litmus paper. Which would she most like
hammer [34]

The correct answer is C.Cabbage juice

6 0
2 years ago
Read 2 more answers
A combustion reaction is represented by __________________.
Ugo [173]

Answer:

The general equation for a complete combustion reaction is: Fuel + O2 → CO2 + H2O. The burning of charcoal is a combustion reaction

8 0
2 years ago
If a 20 kg box is accelerating upward at 8 m/s^2 , what is the magnitude of the upward force
shusha [124]

Answer:

356 N

Explanation:

Newton's second law of motion describes the relationship between an object's mass and the amount of force needed to accelerate it.  

here there is a weight acting downwards on the object , yet it is accelerating  upwards shows that there is a net force upwards

Applying Newtons second law of motion upwards ,

Force  = mass *acceleration

Upward force - m*g = m *a

F_up= 20 *8 + 20 * 9.8

         = 356 N

Upward force= 160 N

7 0
3 years ago
When heat is converted into another form of energy, the total amount of energy is constant. Which law best illustrates this stat
deff fn [24]
The law of conservation of energy states that in a closed or isolated system, the amount of energy remains constant because energy can neither be created or destroyed. It can only be transferred from one form into another. This applies to all forms of energy. 
8 0
3 years ago
How to solve question #2?
Vera_Pavlovna [14]
2a for example the first one,2sec. You know that every second it moves 3metres further. So 2x3=6 but you start at 0.50m so 6+0.50=6.5
5 0
2 years ago
Other questions:
  • What do we call the point where molecules would have 0 kinetic energy?
    9·1 answer
  • What would be the result if Earth's unique atmosphere did not exist?
    10·2 answers
  • Starting from Joe's Gas Station, a car travels due north on Avenue A for 2.4 mi, then turns right and travels on Cedar Street fo
    12·1 answer
  • A ray in plastic has a critical angle of 44.4 deg when trying to enter air. What is the index of refraction for the plastic?
    7·1 answer
  • Some elements have a low degree of freedom and high intermolecular forces between its molecules. These elements are ________ at
    7·2 answers
  • The space shuttle orbits 340km above the surface of the earth.What is the gravitational force on a 9.0kg sphere inside the space
    14·1 answer
  • In a mixture, the ingredients intermingle and
    10·1 answer
  • PLEASE HELP WITH EXPLANATION! I WILL GIVE YOU BRAINLIEST!
    11·1 answer
  • Hi brouhjnhbhb(bhbgvgv&amp;vfc
    15·2 answers
  • Directions: Consider a 2-kg
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!