All categories

2 years ago

Exercises

Physics

1 answer:

Crank2 years ago

5 0

$\\ \rm\Rrightarrow \dfrac{1}{u}+\dfrac{1}{v}=\dfrac{1}{f}$

$\\ \rm\Rrightarrow \dfrac{1}{u}=\dfrac{1}{-10}+\dfrac{1}{38}$

$\\ \rm\Rrightarrow \dfrac{1}{u}=\dfrac{-19+5}{190}$

$\\ \rm\Rrightarrow \dfrac{1}{u}=\dfrac{-14}{190}$

$\\ \rm\Rrightarrow u=\dfrac{190}{-14}$

$\\ \rm\Rrightarrow u=13.6cm$

Real

You might be interested in

1. In Newton’s ring experiment, the diameter of the 5th ring is 0.30 cm and diameter of 15th the ring is 0.62 cm. Find the diame

IgorC [24]

Answer:

Diameter of Newton’s 5th ring = 0.30 cm

Diameter of Newton’s 15th ring = 0.62 cm

Diameter of Newton’s 25th ring = ?

From Newton’s rings experiment we infer that

D2n+m − D2n = 4λmR

For the 5th and 15th rings we have

D215 − D25 = 4λ * 10 * R _______ (1) (m = 10)

For 15th and 25th rings

D225 − D215 = 4λ * 10 * R _______ (2) (m = 10)

We equate the two derivatives

Equation (2) = Equation (1)

D225 − D215 = D215 − D25

D225 = 2D215 – D25

Substituting the values into the equation

D225 = 2 * 0.62 * 0.62 – 0.3 * 0.3 =0.6788 cm2

D25 = 0.8239 cm

4 0

3 years ago

A 70-kg boy is sitting 3 m from the ground in a tree. What is his gravitational potential energy

steposvetlana [31]

m x h x 9.8 m/s squared

70 kg x 3 m x 9.8 m/s squared= 2058 Joules

7 0

3 years ago

"how do the fundamental laws of physics make manifest that space has 3 dimensions?"

bazaltina [42]

If you are asking for a proof on having at least 3 dimensions in space, you can find the physical proof anywhere in your daily life activities. Just the fact that solids have volumes is a proof already that we live in a three-dimensional space. We can move forwards, backwards, sidewards and in all other directions possible.

When you go right into detail, the fundamental laws governing these proofs are very technical. They have differential equations to show as proof. It is too detailed to discuss here. The important things is that, these fundamental laws are what explains the science in our basic activities and natural phenomena:

*Gravitation and planetary motion
* Translation, rotation, magnetic field, forces
* Integrals of equations:

8 0

3 years ago

While walking past a construction site, a person notices a pipe sticking out of a second floor window with water pouring out. As

tia_tia [17]

Answer:

Its diameter increases as it flows down from the pipe. Assuming laminar flow for the water, then Bernoulli's equation can be applied.

P1-P2 + (rho)g(h1 - h2) + 1/2(rho)(v1² - v2²) = 0

Explanation:

P1 = P2 = atmospheric pressure so, P1 - P2 = 0

h1 is greater than h2 so h1-h2 is positive. Rearranging the equation above 2{ (rho)g(h1-h2) + 1/2(rho)v1²}/rho = v2²

From the continuity equation for fluids

A1v1 = A2v2

v2 = A1v1/A2

Substituting into the equation above

(A1v1/A2)² = 2{ (rho)g(h1-h2) + 1/2(rho)v1²}/rho

Making A2² the subject of the formula,

A2² = (A1v1)²× rho/(2{ (rho)g(h1-h2) + 1/2(rho)v1²}

The denominator will be greater than the numerator and as a result the diameter of the flowing stream decreases.

Thank you for reading.

4 0

3 years ago

When will an object dropped from rest attain a speed of 30 m/s?

stich3 [128]

<h3><u>Answer</u> :</h3>

Initial velocity = zero (i.e., free fall)

Final velocity = 30m/s

Acceleration due to gravity = 10m/s²

For a body falling freely under the action of gravity, g is taken positive $.$

◈ <u>First equation of kinenatics</u> :

⇒ v = u + gt

⇒ 30 = 0 + 10t

⇒ t = 30/10

⇒ <u>t = 3s</u>

Hence, object will attain a speed of 30m/s after 3s.

8 0

3 years ago