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
bezimeni [28]
3 years ago
11

A ball is thrown nearly vertically upward from a point near the cornice of a tall building. It just misses the cornice on the wa

y down, and passes a point 160 ft below its starting point 5 sec after it leaves the thrower’s hand. (a) What was the initial velocity of the ball? (b) How high did it rise above its starting point? (c) What was the magnitude of its velocity as it passed a point 64 ft below the starting point?
Physics
1 answer:
vovangra [49]3 years ago
3 0

Answer:

a) 48.5 ft/s

b) 36.5 ft

c) -80.3 ft/s

Explanation:

a)

The equation of motion of the ball is :

y(t) = -16.1 ft/s^2 * t^2 + Vo*t

Where Vo is the initial velocity

If y(5s) = - 160 ft:

-160 ft = -16.1 ft/s^2 * (5 s)^2 + Vo*(5s)

Solving for Vo

Vo  = (16.1*25- 160) ft / 5s = 48.5 ft/s

b)

To answer this question we must first know when the velocity became zero, at this time is when the ball was at its highest point.

v(t) = -32.2 ft/s^2 * t + Vo

t = Vo/32.2ft/s^2 = 1.5 s

And now, the highest point which the ball reached is given by:

y(1.5s) = -16.1 ft/s^2 * (1.5)^2 + Vo*(1.5s)

y(1.5s) = 36.52 ft

c)

We now need the time at which y(t') = -64 ft

-64 = -16.1*t'^2 + 48.5*t'

By means of the quadratic formula, we find that

t' = 4.00498 s ≈ 4 s

And the velocity at t = 4s is:

v(4s) = -32.2 ft/s^2 * 4s +48.5 ft/s = -80.3 ft/s

You might be interested in
Recall specific heat of water is 4186 j/kg/C. Find the specific heat of sample.
Paraphin [41]

Answer:

Shown by explanation;

Explanation:

The heat of the sample = mass ×specific heat capacity of the sample × temperature change(∆T)

Assumption;I assume the mass of the samples are : 109g and 192g

∆T= 30.1-21=8.9°c.

The heat of the samples are for 109g are:

0.109 × 4186 × 8.9 =4060.84J

For 0.192g are;

∆T= 67-30.1-=36.9°c

0.192 × 4186×36.9=29656.97J

5 0
3 years ago
A 8.4-mH inductor carries a current I = Imaxsin ωt, with Imax = 4.00 A and f = ω/2π = 60.0 Hz. What is the self-induced emf as a
Aleks04 [339]

Answer:

E= -3.166 cosωt   V

Explanation:

Given that

I = Imax sinωt

L= 8.4 m H

Imax= 4 A

f = ω/2π = 60.0 Hz

ω = 120π  rad/s

We know that self induce E given as

E=-L\dfrac{dI}{dt}

\dfrac{dI}{dt}= Imax \ \omega\ cos\omega t

E=-L\times Imax \ \omega\ cos\omega t

E=-8.4\times 120\times \pi \ cos\omega t

E= -3166.72 cosωt  m V

E= -3.166 cosωt   V

This is the induce emf.

3 0
3 years ago
The gravitational force,F, on a rocket at a distance,r, from the center of the earth isgiven byF=kr2wherek= 1013N·km2. (Newton·k
Brrunno [24]

Answer:

The gravitational force changing velocity is

\frac{dF}{dt}=-8\frac{N}{s}

Explanation:

The expression for the gravitational force is

F=\frac{k}{r^{2}}\\\\k=10x10^{13} N*km^{2}\\\\r=10x10^{4} km\\\\V=0.4 \frac{km}{s}

Differentiate the above equation

\frac{dF}{dt}=\frac{k}{r^{2}}\\\frac{dF}{dt}=k*r^{-2}\\\frac{dF}{dt}=-2*k*r^{-3} \frac{dr}{dt}\\\frac{dF}{dt}=\frac{-2k}{r^{3}}\frac{dr}{dt}

The velocity is the distance in at time so

V=\frac{dr}{dt}=0.4 \frac{km}{s}

\frac{dF}{dt}=\frac{-2*k}{r^{3}}*0.4\\\frac{dF}{dt}=\frac{-8*10x^{13}N*km^{2} }{(10x10^{4}) ^{3}} \\\frac{dF}{dt}=\frac{-8x10^{12} }{1x10^{12}}

\frac{dF}{dt}=-8\frac{N}{s}

8 0
3 years ago
Which of the following instrument measure time most accurately
valkas [14]
C. Quarts watches is the correct answer
8 0
3 years ago
A ball is launched with initial speed v from the ground level up a frictionless hill. The hill becomes steeper as the ball slide
Triss [41]

Answer:

H(max) = (v²/2g)

Explanation:

The maximum height the ball will climb will be when there is no friction at all on the surface of the hill.

Normally, the conservation of kinetic energy (specifically, the work-energy theorem) states that, the change in kinetic energy of a body between two points is equal to the work done in moving the body between the two points.

With no frictional force to do work, all of the initial kinetic emergy is used to climb to the maximum height.

ΔK.E = W

ΔK.E = (final kinetic energy) - (initial kinetic energy)

Final kinetic energy = 0 J, (since the body comes to rest at the height reached)

Initial kinetic energy = (1/2)(m)(v²)

Workdone in moving the body up to the height is done by gravity

W = - mgH

ΔK.E = W

0 - (1/2)(m)(v²) = - mgH

mgH = mv²/2

gH = v²/2

H = v²/2g.

7 0
3 years ago
Other questions:
  • Which word means "to get away from something"? <br> a become b dream c escape d practice
    14·1 answer
  • What does Newton’s law of universal gravitation say about the distance between objects?
    15·1 answer
  • What is the primary ingredient of power yoga?
    13·1 answer
  • A ball is thrown downward with an initial speed of 7m/s. the balls velocity after 3 seconds is m/s
    9·2 answers
  • It takes a car one minute to go from rest to 30m/s east. Whqt is the acceleration of this car?
    15·1 answer
  • Which of these is outside of the solar system? sun Saturn galaxy moon
    11·2 answers
  • Dissolved in many gasolines are cleaning agents and anti-knock additives. These cleaning agents and additives are an example of
    9·2 answers
  • Question 2 Multiple Choice Worth 2 points)
    14·1 answer
  • 25. The best description of scissor is:
    8·1 answer
  • A body accelerates uniformly from rest at 2ms² for 5 seconds . calculate its average velocity in this time.​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!