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
denpristay [2]
3 years ago
10

(1 point) A street light is at the top of a 25 ft pole. A 4 ft tall girl walks along a straight path away from the pole with a s

peed of 6 ft/sec. At what rate is the tip of her shadow moving away from the light (ie. away from the top of the pole) when the girl is 45 ft away from the pole?

Physics
1 answer:
Andreas93 [3]3 years ago
5 0

Answer:

\frac{dx}{dt}=7.14m/s

Explanation:

As is showed at the figure annexed, we can solve this problem finding the relation between the girl displacement and the shadow displacement.

Relation the triangles (see figure annexed):

\frac{x}{H}=\frac{x-y}{h}\\x=\frac{H}{H-h}y

We derive in order to find the speed of the shadow, because:

dx/dt: shadow's speed

dy/dt: girl's speed

\frac{dx}{dt} =\frac{25}{25-4}*6=7.14m/s

You might be interested in
When two oppositely charged electrodes are immersed in a solution, positively charged ions are attracted to the negative electro
e-lub [12.9K]

Answer:

conductivity of solution is reduced.

Explanation:

When two oppositely charged electrodes are immersed in a solution, positively charged ions are attracted to the negative electrode and gain electrons. The negatively charged ions are attracted to the positive electrode and release electrons.

Due to the process mentioned above , the negatively charged ions are accumulated at the positive electrode and the positively charged ions are accumulated at the negative electrode . This accumulation prevents further attraction of ions at oppositely charged electrodes because the incoming ions face repulsion from already accumulated ions at electrodes.  Further , it creates an emf acting in opposite direction . It reduces the current through the solution. Hence conductivity of solution is reduced.

5 0
3 years ago
Humans start from a single cell. Eventually, as cells divide, they start to differentiate, or specialize. Some cells are special
Margaret [11]

Answer:

interphase im sure

Explanation:

6 0
3 years ago
A toy rocket is fired vertically into the air from the ground at an initial velocity of 80 feet per second. Find the time it wil
miskamm [114]

Answer: 16.3 seconds

Explanation: Given that the

Initial velocity U = 80 ft/s

Let's first calculate the maximum height reached by using third equation of motion.

V^2 = U^2 - 2gH

Where V = final velocity and H = maximum height.

Since the toy is moving against the gravity, g will be negative.

At maximum height, V = 0

0 = 80^2 - 2 × 9.81 × H

6400 = 19.62H

H = 6400/19.62

H = 326.2

Let's us second equation of motion to find time.

H = Ut - 1/2gt^2

Let assume that the ball is dropped from the maximum height. Then,

U = 0. The equation will be reduced to

H = 1/2gt^2

326.2 = 1/2 × 9.81 × t^2

326.2 = 4.905t^2

t^2 = 326.2/4.905

t = sqrt( 66.5 )

t = 8.15 seconds

The time it will take for the rocket to return to ground level will be 2t.

That is, 2 × 8.15 = 16.3 seconds

8 0
3 years ago
CISTU U
marusya05 [52]

solution:

radius of steel ball(r)=5cm=0.05m

density of ball =8000kgm

terminal velocity(v)=25m/s^2

density of air( d) =1.29 kgm

now

volume of ball(V)=4/3pir^3=1.33×3.14×0.05^3=0.00052 m^3

density of ball= mass of ball/Volume of ball

or, 8000=m/0.00052

or, m=4.16 kg

weight of the ball (W)= mg=4.16×10=41.6 N

viscous force(F)=6 × pi × eta × r × v

=6×3.14×eta×0.05×25

=23.55×eta

To attain the terminal velocity,

Fiscous force=Weight

or, 23.55× eta = 41.6

or, eta = 1.76

whete eta is the coefficient of viscosity.

5 0
3 years ago
How much potential energy does a 40n block medicine ball gain when it is lifted 5.m
MAVERICK [17]
By definition, the gain in PE (potential energy) is
ΔPE = m*g*h

Given:
mg = 40 N  (Note that m*g = weight)
h = 5 m

ΔPE = (40 N)*(5 m) =200 J

Answer: 200 J

5 0
3 years ago
Read 2 more answers
Other questions:
  • These four surfaces are opaque; that is they reflect or absorb certain rays of light determine the color
    8·1 answer
  • Which state of matter can be compressed?
    9·2 answers
  • Where on the Earth would you have to be to see the North Celestial Pole exactly halfway between your horizon and zenith?
    6·1 answer
  • A toy rocket is launched vertically from ground level (y = 0.00 m), at time t = 0.00 s. The rocket engine provides constant upwa
    6·1 answer
  • In an element’s square on the periodic table, the number with the greatest numerical value represents the
    7·2 answers
  • An electrically neutral atom has 11 protons. How many electrons will it have orbiting around it’s nucleus?
    10·1 answer
  • HELPPPPPPPPPPPPPPPPPP OMGGGGGGGGGGGGGGGGGGGGGGG
    9·1 answer
  • You walk 200m south, then 50m east. What is your displacement?
    5·1 answer
  • The following are ways to properly manage your stress except
    6·1 answer
  • Which of the following courses might a mechanical engineer take in college?
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!