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3 years ago

A convex lens has a focal length of 0.33 m. The object distance is 0.7 m. What is the image distance?

Physics

1 answer:

dimulka [17.4K]3 years ago

7 0

Answer:

Explanation:

1/v - 1/u = 1/f

given, f = 0.3 m, u = -0.4m

so, 1/v - 1/-0.4 = 1/0.3

or, 1/v = 1/0.3 - 1/0.4 = 1/1.2

v = 1.2 m

now, differentiating 1/v - 1/u = 1/f with respect to t,

-1/v² dv/dt + 1/u² du/dt = 0

or, dv/dt = (v/u)² du/dt

putting, du/dt = 0.01 m/s , v = 1.2 m and u = -0.4 m

so, dv/dt = (1.2/-0.4)² × 0.01

= 0.09 m/s

hence, speed of image with respect to lens is 0.09 m/s .

from formula of magnification

magnification, m = v/u

differentiating with respect to time both sides,

dm/dt = (u dv/dt - vdu/dt)/u²

= (-0.4 × 0.09 - 1.2 × 0.01)/(-0.4)²

= (-0.036 - 0.012)/0.16

= -0.048/0.16

= -0.3 m/s

hence, magnitude of rate of change of lateral magnification is 0.3 m/s

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A ball rolls from point A to point B. The total energy of the ball at point A isn’t the same as the sum of its potential energy

rusak2 [61]

Answer:

option b

Explanation:

because the law of conservation

it means that energy can never created nor be destroyed

even it will change into another form if energy

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3 years ago

The quark composition of the proton and neutron are, respectively, uud and udd, where u is an up quark (charge +23e) and d is a

ludmilkaskok [199]

Answer:

Option C=> π+.

Explanation:

Just as it is given in the question above, we can see that the addition or combination of proton and neutron gives what is known as QUARKS.

Quarks are not easily measured because one can not see and study a quark independently; quarks move in multiples together.

The study of Quarks is very important in physics because they relate very well with electromagnetic force, strong force, weak force and Gravitational force.

"...When the remaining quarks combine to form a single particle, it is a π+".

π+ is a meson or a pion and it contains quarks and anti-quarks too

8 0

3 years ago

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arr

Nitella [24]

Answer:

1. Part A: 648N
2. Part B: 324J
3. Part C: 1,296N

Explanation:

1. Part A:

The magnitude of the force is calculated using the Hook's law:

$|F|=k\Delta x$

You know $\Delta x=0.250m$ but you do not have $k$ .

You can calculate it using the equation for the work-energy for a spring.

The work done to compress the springs a distance $\Delta x$ is:

$Work=\Delta PE=(1/2)k(\Delta x)^2$

Where $\Delta PE$ is the change in the elastic potential energy of the "spring".

Here you have two springs, but you can work as if they were one spring.

You know the work (81.0J) and the length the "spring" was compressed (0.250m). Thus, just substitute and solve for k:

$81.0J=(1/2)k(0.250m)^2\\\\k=2,592N/m$

In reallity, the constant of each spring is half of that, but it is not relevant for the calculations and you are safe by assuming that it is just one spring with that constant.

Now calculate the magnitude of the force:

$|F|=k\Delta x=2,592N/m\times 0.250m=648N$

2. Part B. How much additional work must you do to move the platform a distance 0.250 m farther?

The additional work will be the extra elastic potential energy that the springs earn.

You already know the elastic potential energy when Δx = 0.250m; now you must calculate the elastic potential energy when Δx = 0.250m + 0.250m = 0.500m.

$\Delta E=(1/2)2,592n/m\times(0.500m)^2=324J$

Therefore, you must do 324J of additional work to move the plattarform a distance 0.250 m farther.

3. Part C

What maximum force must you apply to move the platform to the position in Part B?

The maximum force is when the springs are compressed the maximum and that is 0.500m

Therefore, use Hook's law again, but now the compression length is Δx = 0.500m

$|F|=k\Delta x=2,592N/m\times 0.500m =1,296N$

8 0

3 years ago

The basic life function of an organism are carried on by

Lana71 [14]

I believe the answer is a: cells.

3 0

3 years ago

a 300kg motorboat is turned off as it approaches a dock and coasts towards it at .5 m/s. Isaac, whose mass is 62 kg jumps off th

Zolol [24]

-- Before he jumps, the mass of (Isaac + boat) = (300 + 62) = 362 kg,
their speed toward the dock is 0.5 m/s, and their linear momentum is

Momentum = (mass) x (speed) = (362kg x 0.5m/s) = 181 kg-m/s

relative to the dock. So this is the frame in which we'll need to conserve
momentum after his dramatic leap.

After the jump:

-- Just as Isaac is coiling his muscles and psyching himself up for the jump,
he's still moving at 0.5 m/s toward the dock. A split second later, he has left
the boat, and is flying through the air at a speed of 3 m/s relative to the boat.
That's 3.5 m/s relative to the dock.

His momentum relative to the dock is (62 x 3.5) = 217 kg-m/s toward it.

But there was only 181 kg-m/s total momentum before the jump, and Isaac
took away 217 of it in the direction of the dock. The boat must now provide
(217 - 181) = 36 kg-m/s of momentum in the opposite direction, in order to
keep the total momentum constant.

Without Isaac, the boat's mass is 300 kg, so

(300 x speed) = 36 kg-m/s .

Divide each side by 300: speed = 36/300 = 0.12 m/s , away from the dock.
=======================================

Another way to do it . . . maybe easier . . . in the frame of the boat.

In the frame of the boat, before the jump, Isaac is not moving, so
nobody and nothing has any momentum. The total momentum of
the boat-centered frame is zero, which needs to be conserved.

Isaac jumps out at 3 m/s, giving himself (62 x 3) = 186 kg-m/s of
momentum in the direction toward the dock.

Since 186 kg-m/s in that direction suddenly appeared out of nowhere,
there must be 186 kg-m/s in the other direction too, in order to keep
the total momentum zero.

In the frame of measurements from the boat, the boat itself must start
moving in the direction opposite Isaac's jump, at just the right speed
so that its momentum in that direction is 186 kg-m/s.
The mass of the boat is 300 kg so
(300 x speed) = 186

Divide each side by 300: speed = 186/300 = 0.62 m/s away from the jump.

Is this the same answer as I got when I was in the frame of the dock ?
I'm glad you asked. It sure doesn't look like it.

The boat is moving 0.62 m/s away from the jump-off point, and away from
the dock.
To somebody standing on the dock, the whole boat, with its intrepid passenger
and its frame of reference, were initially moving toward the dock at 0.5 m/s.
Start moving backwards away from that at 0.62 m/s, and the person standing
on the dock sees you start to move away from him at 0.12 m/s, and that's the
same answer that I got earlier, in the frame of reference tied to the dock.

yay !

By the way ... thanks for the 6 points. The warm cloudy water
and crusty green bread are delicious.

4 0

3 years ago