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
scoundrel [369]
3 years ago
9

You throw a small rock straight up from the edge of a highway bridge that crosses a river. The rock passes you on its way down,

5.00 s after it was thrown. What is the speed of the rock just before it reaches the water 22.0 m below the point where the rock left your hand? Ignore air resistance.
Physics
1 answer:
Agata [3.3K]3 years ago
7 0

Answer:

Explanation:

for vertical movement , time to reach the top = time to reach the hand = 2.5 s

v = u - gt

At the top , v = 0 , time t = 2.5 s

0 = u - g x 2.5

u = 2.5 x 9.8 = 24.5 m /s

velocity of throw = 24.5 m /s

So , when it passes the hand on its way down , it will have velocity equal to 24.5 m /s and it will accelerate downwards . Let its velocity down by 22 m be v

v² = u² + 2 g s

= 24.5² + 2 x 9.8 x 22

= 600.25 + 431.2

= 1031.45

v = 32.11 m /s .

You might be interested in
"A toy airplane flies clockwise at a constant speed in a horizontal circle of radius 8.0 meters. The magnitude of the accelerati
Citrus2011 [14]

For the answer to the question above, so at the instant, the acceleration of the airplane is southward, the direction of the velocity is also southward. The direction should be the same because it is both a vector quantity and it does not make sense if the direction and acceleration have different direction.
6 0
3 years ago
Read 2 more answers
How and why does air pressure change with altitude in the atmosphere?
wlad13 [49]
Pressure with Height: pressure decreases with incrementing altitude. The pressure at any caliber in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a homogeneous surface at lower calibers.
5 0
3 years ago
A 3 kg bowling ball is thrown onto a mattress. If it takes 0.3 seconds to stop the ball using a force of 24 N, what was the init
enyata [817]

Answer:

-24 m/s

Explanation:

mass of the bowling ball =  3 kg

time (t) = 0.3 seconds

Force = 24 N

initial velocity u = ???

We know that;

Force = mass × acceleration (a)

So;

24 = 3 × a

a = 24/3

a = 8 m/s²

Also;

From equation of motion; acceleration is given by the relation;

a =\frac{v-u}{t}

if v = 0

then ;

8 = \frac{0-u}{0.3}

24 = 0- u

u = -24 m/s

Thus; the  initial velocity of the bowling ball when it first touched the mattress =  -24 m/s

7 0
3 years ago
Melvin is traveling south on I-95 at 29 m/s (65 mph) when a deer jumps into his path, 50 m ahead. a. If his reaction time is 0.1
aleksandr82 [10.1K]

Answer:

a. 5.22 meters

b. 2.9 seconds

c. No, Melvin does not hit the deer

Explanation:

The parameters with which Melvin is travelling are as follows;

The speed of Melvin's motion, u = 29 m/s

The distance from Melvin at which the deer jumps into the path = 50 m

a. Distance, d = Velocity, u × Time, t

The time it takes Melvin to react = 0.18 seconds

The distance, "d₁" Melvin travels before his foot hits the break = The velocity with which Melvin was traveling, "u" × The time duration it takes Melvin to hit the brakes, "t₁"

∴ d₁ = 29 m/s × 0.18 s = 5.22 m

The distance, Melvin travels before his foot hits the break = d₁ = 5.22 m

b. Melvin's acceleration after his foot hits the brakes, a = -10 m/s²

Therefore, we have;

The time it takes "t₂" it takes for him to come to a complete stop given as follows;

y = u + a × t₂

Where;

v = The final velocity after Melvin comes to a complete stop = 0 m/s

By substituting the known values, we have;

0 = 29 m/s + (-10 m/s²) × t₂ = 29 m/s - 10 m/s² × t₂

∴ 29 m/s = 10 m/s² × t₂

t₂ = (29 m/s)/(10 m/s²) = 2.9 s

The time it takes it takes for him to come to a complete stop = t₂ = 2.9 s

c. The distance, "d₂", Melvin reaches while accelerating (decelerating) at -10 m/s² to come to a complete stop is given as follows;

v² = u² + 2·a·d₂

Therefore, we have;

0² = (29 m/s)² + 2 × (-10 m/s) × d₂ = (29 m/s)² - 2 × 10 m/s × d₂

∴  (29 m/s)² = 2 × 10 m/s × d₂

d₂ = ((29 m/s)²)/(2 × 10 m/s²) = (841 m²/s²)/(20 m/s²) = 42.05 m

The distance, Melvin reaches while accelerating (decelerating) at -10 m/s² to come to a complete stop = d₂ = 42.05 m

Given that d₂ = 42.05 m < 50 m (The distance separating Melvin's initial location and the deer, Melvin does not hit the deer.

3 0
3 years ago
when a constant force acts upon an object the acceleration of the object varies inversely with its mass. when a certain constant
solong [7]

Explanation:

When a constant force acts upon an object the acceleration of the object varies inversely with its mass.

a\propto \dfrac{1}{m}

or

\dfrac{a_1}{a_2}=\dfrac{m_2}{m_1}

If m₁ = 21 kg, a₁ = 3 m/s², m₂ = 9 kg

We need to find a₂

So,

a_2=\dfrac{m_1a_1}{m_2}\\\\a_2=\dfrac{21\times 3}{9}\\\\a_2=7\ m/s^2

So, if mass is 9 kg, its acceleration is 7 m/s².

8 0
3 years ago
Other questions:
  • Identify the false statement: Select one:
    12·2 answers
  • A container of negligible heat capacity has in it 456 g of ice at - 25 . 0°C . Heat is supplied to the container at the rate of
    10·1 answer
  • When heat is converted into another form of energy, the total amount of energy is constant. Which law best illustrates this stat
    6·2 answers
  • A boy and a girl are riding a merry- go-round which is turning ata constant rate. The boy is near the outer edge, while a girl i
    10·1 answer
  • The electrical resistance of a wire varies directly as its length and inversely as the square of its diameter. a wire with a len
    11·1 answer
  • The heater element of a particular 120-V toaster is a 8.9-m length of nichrome wire, whose diameter is 0.86 mm. The resistivity
    5·1 answer
  • what are geology,astronomy,and physics is the answer hypothesis,scientific inquiries,scientific discplines,or protocols?
    15·1 answer
  • Para investigar - Posición del cuerpo en general. - Posición de la cabeza. - Posición de los brazos y manos. - Apoyo de los pies
    5·1 answer
  • 30 kg sits on a table the acceleration due to gravity is 10 m/s^2 what force does the table exert on the television.
    13·1 answer
  • What is the Sl unit for momentum?<br> O kg• m<br> O kg<br> O kg• m<br> O kg<br> 2<br> m
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!