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
Molodets [167]
3 years ago
9

1.An elevator is ascending with constant speed of 10 m/s. A boy in the elevator throws a ball upward at 20 m/ a from a height of

2 m above the elevator floor when the elevator floor when the elevator is 28 m above the ground.
a. What's the maximum height?
b. How long does it take for the ball to return to the elevator floor?​
Physics
1 answer:
laiz [17]3 years ago
6 0

(a) The maximum height reached by the ball from the ground level is 75.87m

(b) The time taken for the ball to return to the elevator floor is 2.21 s

<u>The given parameters include:</u>

  • constant velocity of the elevator, u₁ = 10 m/s
  • initial velocity of the ball, u₂ = 20 m/s
  • height of the boy above the elevator floor, h₁ = 2 m
  • height of the elevator above the ground, h₂ = 28 m

To calculate:

(a) the maximum height of the projectile

total initial velocity of the projectile = 10 m/s + 20 m/s  = 30 m/s (since the elevator is ascending at a constant speed)

at maximum height the final velocity of the projectile (ball), v = 0

Apply the following kinematic equation to determine the maximum height of the projectile.

v^2 = u^2 + 2(-g)h_3\\\\where;\\\\g \ is \ the \ acceleration \ due \ to\  gravity = 9.81 \ m/s^2\\\\h_3 \ is \ maximum \ height \ reached \ by \ the \ ball \ from \ the \ point \ of \ projection\\\\0 = u^2 -2gh_3\\\\2gh_3 = u^2 \\\\h_3 = \frac{u^2}{2g} \\\\h_3 = \frac{(30)^2}{2\times 9.81} \\\\h_3 = 45.87 \ m

The maximum height reached by the ball from the ground level (h) = height of the elevator from the ground level + height of he boy above the elevator + maximum height reached by elevator from the point of projection

h = h₁ + h₂ + h₃

h = 28 m + 2 m  +  45.87 m

h = 75.87 m

(b) The time taken for the ball to return to the elevator floor

Final height of the ball above the elevator floor = 2 m + 45.87 m = 47.87 m

Apply the following kinematic equation to determine the time to return to the elevator floor.

h = vt + \frac{1}{2} gt^2\\\\where;\\\\v \ is \ the \ initial \ velocity \ of \ the \ ball \ at \ the \ maximum \ height = 0\\\\h = \frac{1}{2} gt^2\\\\gt^2 = 2h\\\\t^2 = \frac{2h}{g} \\\\t = \sqrt{\frac{2h}{g}} \\\\t = \sqrt{\frac{2\times 47.87}{9.81}} \\\\t = 2.21 \ s

To learn more about projectile calculations please visit: brainly.com/question/14083704

You might be interested in
On a hot summer day in the state of Washington while kayaking, I saw several swimmers jump from a railroad bridge into the Snoho
Svetlanka [38]

Answer: part a: 19.62m

part b: 19.62 m/s

part a: 2.83 secs

Explanation:If the air resistance is ignored then the swimmer experience free fall under gravity hence

u=0

a=9.81 m/s2

t=2 secs

s=ut+0.5at^2

s=h

h=0*2+0.5*9.81*2^2\\h=19.62 meters

Part b

v=u+at\\v=0+9.81*2\\v=19.62m/s

Part c

now we have h=2*19.62=39.24

39.24=0+0.5*9.81*t^2\\t^2=8\\t=2.83 secs

4 0
3 years ago
TIME REMISE
SCORPION-xisa [38]

Answer:

It is conserved

Explanation:

5 0
3 years ago
Read 2 more answers
A car drives 215 km east and then 45 km north. What is the magnitude of the car’s displacement? Round your answer to the nearest
34kurt

Displacement = (straight-line distance between the start point and end point) .

Since the road east is perpendicular to the road north,
the car drove two legs of a right triangle, and the magnitude
of its final displacement is the hypotenuse of the triangle.

    Length of the hypotenuse = √ (215² + 45²)

                                              =  √ (46,225 + 2,025)

                                              =   √ 48,250

                                              =       219.7 miles .

8 0
3 years ago
Read 2 more answers
Starting from rest, a particle that is confined to move along a straight line is accelerated at a rate of 5.0 m/s2. Which one of
Elanso [62]

Answer:

c) The slope is not constant and increases with increasing time.

Explanation:

The equation for the position of this particle (starting from rest is)

s = at^2/2 = 5t^2/2 = 2.5t^2

We can take derivative of this with respect to time t to get the equation of slope:

s' = (2.5t^2)' = 2*2.5t = 5t

As time t increase, the slope would increases with time as well.

6 0
3 years ago
The distance between Earth and Mars is 225 million km. When converted using the conversion factor 1 AU = 1.5 × 108 km, the dista
noname [10]
To convert km to AU, we divide 225,000,000 km by the factor of 1.5 x 10^8 = 150,000,000 km. This gives us 225,000,000 / 150,000,000 = 1.5 AU. Therefore, the distance between Earth and Mars in AU is 1.5 AU.
The AU is not equivalent to a light-year. A light-year is equivalent to around 9.5 x 10^12 kilometers.

4 0
3 years ago
Other questions:
  • Professor Frank Nabarro insists that all senior physics majors take his notorious physics aptitude test. The test is so tough th
    5·1 answer
  • Which light consists of all the colors of the visible light<br> spectrum?
    13·1 answer
  • The emf induced in a coil that is rotating in a magnetic field will be at a maximum at which moment?
    9·1 answer
  • What is the difference between the organic material from which coal forms and the organic material from which petroleum and natu
    15·1 answer
  • What is the restoring force of a spring with a spring constant of 4a and a stretched displacement of 3b? A. –7 ab B. `-7 a/b ` C
    9·1 answer
  • What drives people to explore
    12·1 answer
  • The gravitational potential energy of an object is due to
    10·1 answer
  • What is the change in internal energy (in J) of a system that releases 675 J of thermal energy to its surroundings and has 525 c
    11·1 answer
  • explain the production of current with the help of a magnet and describe which device works on this phenomena
    7·1 answer
  • Which is a unit to measure air pressure?
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!