All categories

3 years ago

Earning Goal: To be able to calculate work done by a constant force directed at different angles relative to displacement

Physics

1 answer:

lana [24]3 years ago

8 0

Answer:

the work done by the 30N force is 4156.92 J.

For this problem, they don´t ask you to determine the work of the total force applied in the block. They only want the work done for the force of 30N, with an angle of 30º respectively of the displacement and a traveled distance of 160m. So:

W=F·s·cos(α)=30N·160m·cos(30º)=4156.92J

You might be interested in

A 0.45 kg soccer ball changes its velocity by 20.0 m/s due to a force applied to it in 0.10 seconds. What force was necessary fo

Sonja [21]

For this problem, we will need the famous equation F=ma, as detailed by Isaac Newton.

F=mass x acceleration, where Force is in Newtons.

20 m/s represents the quantity of speed change, but to use in the equation, we need acceleration, not speed. Acceleration is the velocity change over a unit time, so changing 20 m/s in 0.1 seconds means that the acceleration was 200 m/s^2.

Plugging in all your numbers, you find:

F=(0.45 kg)(200 m/s^2) = 90 N of force.

6 0

3 years ago

A 0.9 kg ball attached to a cord is whirled in a vertical circle of radius 2.5 m. Find the minimum speed needed at the top of th

lapo4ka [179]

Answer:

The minimum speed needed at the top of the circle so that the cord remains tensioned and the ball's path remains circular is approximately is 9.903 meters per second.

Explanation:

By the Principle of Energy Conservation we understand that the minimum speed needed by the ball is that speed such that maximum height reached is equal to the diameter of the vertical circle, that is:

$K =U_{g}$ (1)

Where:

$K$ - Translational kinetic energy, measured in joules.

$U_{g}$ - Gravitational potential energy, measured in joules.

By definitions of translational kinetic and gravitational potential energies, we expand the equation above and clear the initial speed of the ball:

$\frac{1}{2}\cdot m \cdot v^{2} = m\cdot g\cdot h$

$v = \sqrt{2\cdot g\cdot h}$ (2)

Where:

$m$ - Mass, measured in kilograms.

$v$ - Initial speed, measured in meters per second.

$g$ - Gravitational acceleration, measured in meters per square second.

$h$ - Maximum height of the ball, measured in meters.

If we know that $g = 9.807\,\frac{m}{s^{2}}$ and $h = 5\,m$ , then the initial speed of the ball is:

$v = \sqrt{2\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (5\,m)}$

$v\approx 9.903\,\frac{m}{s}$

The minimum speed needed at the top of the circle so that the cord remains tensioned and the ball's path remains circular is approximately is 9.903 meters per second.

3 0

3 years ago

In static electricity what are the subatomic particles, their charges, their location in the atom

enot [183]

Electrons - have a negative charge and orbit the nucleus
Protons - have a positive charge and are located in the nucleus
Neutrons - have no charge and are also located in the nucleus

6 0

4 years ago

A film of soapy water on top of a plastic cutting board has a thickness of 255 nm. What wavelength and color is most strongly re

Alona [7]

Answer:

the reflected wavelength is lano = 4.55 10⁻⁷ m which corresponds to the blue color

Explanation:

This is a case of reflection interference, we must be careful

* There is a 180º phase change when light passes from the air to the soap film (n = 1,339), but there is no phase change when passing from the pomp to the plastic (n = 1.3)

* the wavelength within the film is modulated by the refractive index

λₙ = λ₀ / n

if we consider these relationships the condition for constructive interference is

2 t = (m + ½) λₙ

2t = (m + ½) λ₀ / n

λ₀ = 2t n / (m + ½)

we substitute the values

λ₀= 2 255 10⁻⁹ 1,339 / (m + ½)

λ₀ = 6.829 10⁻⁷ (m + ½)

let's calculate the wavelength for various interference orders

m = 0

λ₀ = 6.829 10⁻⁷/ ( 0 + ½ )

λ₀ = 13.6 10⁻⁷

it is not visible

m = 1

λ₀ = 6,829 10⁻⁷/ (1 + ½)

λ₀ = 4.55 10⁻⁷

color blue

m = 2

λ₀ = 6.829 10⁻⁷ / (2 + ½)

λ₀ = 2,7 10⁻⁷

it is not visible

therefore the reflected wavelength is lano = 4.55 10⁻⁷ m which corresponds to the blue color

5 0

3 years ago

On a balanced seesaw, a boy three times as heavy as his partner sits

slega [8]

Answer:

1/3 the distance from the fulcrum

Explanation:

On a balanced seesaw, the torques around the fulcrum calculated on one side and on another side must be equal. This means that:

$W_1 d_1 = W_2 d_2$

where

W1 is the weight of the boy

d1 is its distance from the fulcrum

W2 is the weight of his partner

d2 is the distance of the partner from the fulcrum

In this problem, we know that the boy is three times as heavy as his partner, so

$W_1 = 3 W_2$

If we substitute this into the equation, we find:

$(3 W_2) d_1 = W_2 d_2$

and by simplifying:

$3 d_1 = d_2\\d_1 = \frac{1}{3}d_2$

which means that the boy sits at 1/3 the distance from the fulcrum.

8 0

4 years ago