A disc at rest without slipping, rolls down a hill of height (3×9.8)m.What is its speed when it reaches at the bottom?

Answers

Answer 1

Answer:

The speed as it reaches the bottom is  24m/s

Explanation:

Given parameters:

   Height of hill  = (3 x 9.8)m = 29.4m

Unknown:

Final speed as it reaches the bottom = ?

Solution:

 To solve this problem, we apply;

    v² = u² + 2gh

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity = 9.8m/s²

h is the height

note, the initial speed of the body is 0;

Input the parameters and solve;

    v² = 0² + 2 x 9.8 x 29.4

   v² = 576.24

   v = √576.24  = 24m/s

The speed as it reaches the bottom is  24m/s


Related Questions

Two boxes of masses 3M and 5M are attached by a massless rope. They are being pulled to the right with a constant force of P = 800 N, which allows them to just overcome static friction, with a μs= 0.70 between the floor and the boxes.
a. Find M.
b. Find the Tension in the rope between the two boxes.

Answers

Answer:

  a) about 14.577 kg

  b) 300 N

Explanation:

b) In order for the acceleration to be the same for each mass, the 800 N force must be divided between the boxes in proportion to their mass. That is, the net force on the 5M mass must be 5/8 of the total force, or 500 N. Then the tension in the rope is 800 N -500 N = 300 N, which is 3/8 of 800 N.

Tension: 300 N

__

a) The total mass is 8M, and the total normal force on the floor is ...

  F = ma = (8M)(9.8 m/s^2)

The friction force is 0.7 times this, and is equal to the 800 N force pulling on the boxes.

  800 N = (8M)(9.8 m/s^2)(0.7)

  M = 800/(8·9.8·0.7) kg ≈ 14.577 kg

A spring is stretched from rest and released. Which of the following describes the
frequency of the spring?
A:the speed of the spring as it passes through the equilibrium position
B: the number of times the spring moves up and down in 1 second
C:the time it takes the spring to compress and then expand once
D: the number of coils on the spring

Answers

Explanation:

you have given two questions which one to answer

A plastic block of dimensions 2.00 cm x 3.00 cm x 4.00 cm has a mass of 30.0 g. What is its density?

Answers

Answer:

1.25 g/cm^3

Explanation:

mass-30.0g

volume- 4cm×2cm×3cm=24cm^3

density?

*to find density

Density=Mass/Volume

=30÷24

=1.25g/cm^3

Newton's first law states that objects do not change their motion unless acted upon by a net force. What does the word 'net' mean in this context?
A woven net, such as a fishing net or basketball net
B To catch or ensnare
C Remaining or left over after everything has been accounted for
D To cover, such as with mosquito netting​

Answers

Answer it is b is the best option to pick A, does that make sense


The interaction between electrical energy and magnetism has been an important
topic in 20th century science, Which term describes this interaction?

Answers

Answer:

Maybe

Explanation:

I say maybe because it will help them still but not quite


3.what does this stand for ??

Answers

Answer:

see below

Explanation:

The triangle stands for the change in

We would change the change in x

Answer:

Δ This is the symbol of Delta which means Change

and x is length/distance/position.

Thus, Δx stands for Change in length/distance/position.

-TheUnknownScientist

At which point on the image to the right would the ball have the greatest velocity if it moved from A to G.

please help me out.

A


B


C


D


E


F


G

Answers

Answer:

Total energy = Kinetic Energy + Potential Energy = Constant

Since the potential energy is lowest at point D the kinetic energy will be greatest at point D and the velocity will be the greatest.

This diagram shows two different forces acting on a skateboarder. The
combined mass of the skateboard and the person is 81.5 kg. Based on this
information, what is the acceleration of the skateboarder?
Air resistance = 11.40 N
mi
Applied force = 52.80
A. 0.51 m/s2 to the left
O B. 1.94 m/s2 to the right
O C. 1.94 m/s2 to the left
O D. 0.51 m/s2 to the right

Answers

Answer:

Option D. 0.51 m/s² to the right.

Explanation:

The following data were obtained from the question:

Force applied (Fₐ) = 52.8 N

Force resistance (Fᵣ) = 11.4 N

Mass = 81.5 kg

Acceleration (a) =.?

Next, we shall determine the net force (Fₙ). This can be obtained as follow:

Force applied (Fₐ) = 52.8 N

Force resistance (Fᵣ) = 11.4 N

Net force (Fₙ) =?

Fₙ = Fₐ – Fᵣ

Fₙ = 52.8 – 11.4

Fₙ = 41.4 N to the right

Finally, we shall determine the acceleration of the skateboarder as show below:

Net force (Fₙ) = 41.4 N to the right

Mass = 81.5 kg

Acceleration (a) =..?

F = ma

41.4 = 81.5 × a

Divide both side by 81.5

a = 41.4 / 81.5

a = 0.51 m/s² to the right.

Thus, the acceleration of the skateboarder is 0.51 m/s² to the right.

Answer: .51 to the right

Explanation:

The Intensity level of a loud saw is 100 db at a distance of 5m. At what distance would the level be 80 db

Answers

Answer:

50 m

Explanation:

The relationship between the intensity of sound in dB and distance is given by the formula:

[tex]B_2=B_1+20log(\frac{R_1}{R_2} )\\\\Where \ B_2\ is \ the\ sound\ intensity\ at\ distance\ R_2\ and\\B_1\ is \ the\ sound\ intensity\ at\ distance\ R_1\ \\\\Given\ that: B_1=100\ dB, R_1=5\ m, B_2=80\ dB\\\\B_2=B_1+20log(\frac{R_1}{R_2} )\\\\80=100+20log(\frac{5}{R_2} )\\\\-20=20log(\frac{5}{R_2} )\\\\log(\frac{5}{R_2} )=-1\\\\\frac{5}{R_2}=10^{-1}\\\\\frac{5}{R_2}=0.1\\\\R_2=5/0.1=50\ m[/tex]

Which two types of energy does a book have as it falls to the floor

Answers

Answer:

kinetic and potential energy

Explanation:

Which famous Baroque period composer wrote 46 pieces of music while in jail?

Answers

Answer:

John Sebastian Bach

Answer:

Johann Sebastian Bach

Explanation:

please tell me if i am wrong! thank you!

Open Box. Consider a hollow box with the top missing. The sides have negligible thickness and each has length L and mass m. (a) Find the x-coordinate of the center of mass.

Answers

Answer:

x_{cm} = L / 2

Explanation:

The center of mass is defined by

         [tex]x_{cm}[/tex] = 1 / M ∑ m_{i}  x_{i}

where M is the total mass of the system

in this case the system is continuous so, for which we use the density

      ρ = dm / dx

      dm = ρ dx

substituting

        x_{cm} = 1 / M ∫ x ρ dx

        x_{cm} = ρ / M ∫ x dx

we integrate and evaluate from x = 0 to x = L

        x_{cm} = ρ / M (L² /2 -0)

       

we introduce the density which is constant

        ρ = M / L

        x_{cm} = 1 /M (M/L)  L² / 2

        x_{cm} = L / 2

A cannonball is fired horizontally from a 10 m high cliff at 20 m/s. How long will the cannonball be in the air? How far away will the cannonball strike the ground?

Answers

Answe ¡Buenos días! –

#3 ¡Buenas tardes! –

#4 ¡Bienvenid

A tower crane has a hoist motor rated at 159 hp. If the crane is limited to using 72.0 % of its maximum hoisting power for safety reasons, what is the shortest time in which the crane can lift a 5550 kg load over a distance of 89.0 m

Answers

Answer:

The value is    [tex]t = 56.68 \  s  [/tex]

Explanation:

From the question we are told that

   The rating of the hoist motor is  [tex]k  =  159hp = 159 *746 =118614 \ W[/tex]

    The  percentage of it power used is  [tex]z = 0.72 * 118614=85402.08 \ W[/tex]

      The  mass of the load is m  = 5550 kg

      The distance is  h = 89.0 m

The potential  energy required to lift the load through that distance is

     [tex]E =  m *  g * h[/tex]

=>    [tex]E =  5550 *  9.8 *  89.0[/tex]

=>   [tex]E =  4840710 \ J[/tex]

Generally the time taken is mathematically represented as

       [tex]t = \frac{E}{ z}[/tex]

=>    [tex]t = \frac{4840710}{ 85402.08}[/tex]

=>    [tex]t = 56.68 \  s  [/tex]

A car at the top of a ramp starts from rest and rolls to the bottom of the ramp, achieving a certain final speed. If you instead wanted the car to achieve twice as much speed at the bottom of the ramp, how high should the ramp be compared to the first case

Answers

Answer:

It must be 4 times high.

Explanation:

Assuming that the car can be treated as a point mass, and that the ramp is frictionless, the total mechanical energy must be conserved.This means, that at any time, the following must be true:ΔK (change in kinetic energy) = ΔU (change in gravitational potential energy)

⇒      [tex]m*g*h = \frac{1}{2} * m*v^{2}[/tex]

Let's call v₁, to the final speed of the car, and h₁ to the height of the ramp.

       So, at the bottom of the ramp, all the gravitational potential energy

      must be equal to the kinetic energy of the car (Defining the bottom of

      the ramp as our zero reference for the gravitational potential energy):

       [tex]m*g*h_{1} = \frac{1}{2} * m*v_{1} ^{2}[/tex]  (1)

Now, let's do v₂ = 2* v₁Replacing in (1) we get:

        [tex]m*g*h_{2} = \frac{1}{2} * m*(2*v_{1}) ^{2}[/tex] (2)

Dividing (2) by (1), and rearranging terms, we get:h₂ = 4* h₁

Help me please :)
Answer the following questions to explain the relationship between electricity and magnetism.

• What are the critical components of an electromagnet and what purpose do they each serve?


• How can the strength of an electromagnet be changed?


• Why is an electromagnet considered a temporary magnet?


Answer the following questions about motors and generators.

• What components are needed for a generator to produce electric current?

• Describe motors and generators in terms of energy input and output.




HELP MEEEEEEEE
Decide if the following statements would be found in the Motor or Generator. Answers can be found at the end of the 3.07 Reading.

Statement Motor or Generator?

Answers

Answer:

R u from k12?? i am XD add me on discord my username is Hot Boy#1650

Explanation:

Plates slide past one another at____.
A. Subduction zones
B. Transform boundaries
C. Convection currents
D. Divergent boundaries

Answers

Answer:

Transform Boundary

Explanation:

The just slide past each other

Answer:

Transform Boundaries

Explanation:

a man weighing 490 n on earth weighs only 81.7 n on the moon. His mass on the moon is__kg. (Use g=9.8 m/s2

Answers

Answer:

m = 50 [kg]

Explanation:

In order to solve this problem we must be clear about the difference between weight and mass. Weight is the product of mass by the acceleration of the planet or the star. While the mass is always preserved it never changes regardless of where it is located.

So for the earth we have:

g = gravity acceleration = 9.8 [m/s^2]

m = mass [kg]

W = weigth = 490 [N]

therefore the mass will be:

m = W/g

m = 490/9.8

m = 50 [kg]

Now it is important to remember that the mass will be the same on the moon or on the earth, but the weight will be different, because the gravity acceleration of the moon is different from the gravity acceleration on earth

So the gravity on the moon is equal to:

81.7 = 50 * gm

gm = 1.634 [m/s^2]

SOH-CAH-TOA is used to solve for the ________
velocities in a full/angled projectile.

a. final (x and y)
b. overall
c. initial (x and y)
d. resultant

Answers

Answer:

c. initial (x and y)

Explanation:

When a projectile is launched at a velocity with a launch angle, to solve it, we must first resolve the initial velocity into the x and y components. To do this will mean we have to treat it like a triangle due to the launch angle and the direction of the projectile.

Therefore, we will have to make use of trigonometric ratios which is also known by the mnemonic "SOH CAH TOA"

Thus, this method resolves the initial x and y velocities.

If the body with a mass of 4kg is moved by a force of 20 N, what is the rate of its acceleration?

Answers

Answer:

The answer is 5 m/s²

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

[tex]acceleration = \frac{force}{mass} \\[/tex]

From the question

force = 20 N

mass = 4 kg

We have

[tex]a = \frac{20}{4} \\ [/tex]

We have the final answer as

5 m/s²

Hope this helps you

The diagram shows two forces acting on the dog. What are these two forces

Answers

Answer:

kenietic and potential i guess

Explanation:

What equation relates mechanical energy, thermal energy, and total energy when there is friction present in a system?

Answers

E total = ME + E thermal Explanation:
APEX

give three factors which are responsible for the vanishing forest ​

Answers

Answer:

1. Huge wildfires

2. Deforestation

3. Reduced amount of aforestation, etc

5. A car advertisement states that a certain car can accelerate from rest to 70 m/s in 7
seconds. Find the car's average acceleration.
O-0.10 m/s^2
10 m/s^2
-10 m/s^2
O 0.10 m/s^2

Answers

Answer:

The car's average acceleration is [tex]10\ m/s^2[/tex].

Explanation:

Constant Acceleration Motion

It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.

Being vo the initial speed, a the constant acceleration, vf the final speed, and t the time, the following relation applies:

[tex]v_f=v_o+at[/tex]

If we need to find the acceleration, we solve the above equation for a:

[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]

The car accelerates from rest (vo=0) to vf=70 m/s in t=7 seconds. Substitute the values into the formula:

[tex]\displaystyle a=\frac{70-0}{7}=\frac{70}{7}=10[/tex]

[tex]a=10\ m/s^2[/tex]

The car's average acceleration is [tex]10\ m/s^2[/tex].

Note: The choices are not very clear, but the second choice seems to be the correct answer.

Light of wavelength 580 nm falls on a slit that is 3.70×10−3mm wide. Part A Estimate how far the first brightest diffraction fringe is from the strong central maximum if the screen is 10.0 m away.

Answers

Answer:

Explanation:

wavelength λ = 580 x 10⁻⁹ m

slit width d = 3.7 x 10⁻⁶ m

distance of screen D = 10 m

distance of first bright fringe =  1.5 x λ D / d

= 1.5 x 580 x 10⁻⁹  x 10 / 3.7 x 10⁻⁶

= 2351.34  x 10⁻³ m

= 2351.34 mm .

If an object is moving with a constant velocity to the right, what direction is the net force.

Group of answer choices

A.To the right

B.To the left

C.Net force is 0

D.Not enough information

Answers

Answer:

At constant velocity, his weight equals the force of friction. In other words, there is no net force. If however, he loosens his grip and decreases the friction force, he will accelerate downward.

Explanation:

D
5. Mariam driving at a speed of 20.0 m/s applies
brakes close to a signal and travels a distance of
200 m before coming to rest. What was her
acceleration?
A. -0.50 m/s2
B. -0.70 m/s2
C. -1.00 m/s2
D. -2.00 m/s2
6. A trollen at rest is nushed to accelerate at a

Answers

Answer:

maibi.... D

Explanation:

I think is D

A 30%-efficient car engine accelerates the 1300 kg car from rest to 10 m/s . How much energy is transferred to the engine by burning gasoline

Answers

Answer:

The Energy transferred to the engine by burning gasoline = 216.67 KJ

Explanation:

The parameters given are:

The efficiency of the car engine, E = 30% = 0.3

Mass, m = 1300 kg

Initial velocity, u = 0, since the car is from rest

The final velocity, v = 10 m/s

Since the car was moving, we calculate its kinetic energy.

kinetic energy = ((1/2) (m) (v^2)

((1/2) (1300 kg) (10 m/s^2)

= 65,000 j

The Energy, Q transferred to the engine by burning gasoline in this case

= potential energy / The efficiency of the car engine, E

Q = 65,000 j / 0.3

= 216,666.66 J

Converting Joule to kilojoule

where 1KJ = 1000j

216,666.66 J = 216.67 KJ

A 1400.0 kg car crests a 3200.0 m pass in the mountains and briefly comes to rest. The car descends 1000 m before climbing and cresting a 2800 m pass. (a) Neglecting friction, what should the speed of the car be at the top of the second pass? (b) Find the actual speed of the car if the work due to nonconservative forces is – 5 x106 J.

Answers

Answer:

a) v = 88.54 m/s

b) vf = 26.4 m/s

Explanation:

Given that;

m = 1400.0 kg

a)

by using the energy conservation

loss in potential energy is equal to gain in kinetic energy

mg × ( 3200-2800) = 1/2 ×m×v²

so

1400 × 9.8 × 400 = 0.5 × 1400 × v²

5488000 = 700v²

v² = 5488000 / 700

v² = 7840

v = √7840

v = 88.54 m/s

b)

Work done by all forces is equal to change in KE

W_gravity + W_non - conservative = 1/2×m×(vf² - vi²)

we substitute

1400 × 9.8 × ( 3200-2800) - (5 × 10⁶) = 1/2 × 1400 × (vf²  -0 )

488000 = 700 vf²

vf² = 488000 / 700

vf² = 697.1428

vf = √697.1428

vf = 26.4 m/s

2. A bird flying horizontally at 10 m/s drops a branch. The bird is flying at an altitude of 20 m. Determine
the horizontal displacement it moves relative to where it was dropped.

Answers

Answer:

The horizontal displacement is 20 m.

Explanation:

Given that,

Velocity = 10 m/s

Height = 20 m

We need to calculate the time

Using equation of motion

[tex]s=ut+\dfrac{1}{2}gt^2[/tex]

Put the value into the formula

[tex]20=0+\dfrac{1}{2}\times9.8\times t^2[/tex]

[tex]t^2=\dfrac{20\times2}{9.8}[/tex]

[tex]t=\sqrt{\dfrac{20\times2}{9.8}}[/tex]

[tex]t=2.0\ sec[/tex]

We need to calculate the horizontal displacement

Using formula of horizontal displacement

[tex]\Delta x=v_{x}\times t[/tex]

Put the value into the formula

[tex]\Delta x=10\times2.0[/tex]

[tex]\Delta x=20\ m[/tex]

Hence, The horizontal displacement is 20 m.

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