All categories

3 years ago

At what distance will a 80 W lightbulb have the same apparent brightness as a 120 W bulb viewed from a distance of 40 m

Physics

1 answer:

liq [111]3 years ago

4 0

Answer:

32.6mm

Explanation:

Using area of a sphere(bulb) = 4πr²

So A is proportional to radius²

So the Energy will be proportional to r²

But 120/80 = 1.5 is the energy factor so

Using

1.5/d² = 1/r²

1.5/40²= 1/r^2

r = √( 40²/ 1.5)

r = 32.6m

You might be interested in

It is known as a basic unit of all living things.

andrezito [222]

hello, the answer is..

cell

4 0

2 years ago

It says find the slope for each line I'm stuck on number one can you help me

Allushta [10]

$\text{slope}=\frac{y_2-y_1}{x_2-x_1}$

(-2, -1)(3, 1)

Therefore,

$\text{slope}=\frac{1-(-1)}{3-(-2)}=\frac{1+1}{3+2}=\frac{2}{5}$

7 0

1 year ago

Freud believes that defense mechanisms are reactions people have to protect themselves from uncomfortable feelings. the article

makkiz [27]

Answer:

A: Anxious

Explanation:

got a 100% of Edge

6 0

2 years ago

A man holding a rock sits on a sled that is sliding across a frozen lake (negligible friction) with a speed of 0.550 m/s. The to

Arisa [49]

Answer: 0.5 m/s

Explanation:

Given

Speed of the sled, v = 0.55 m/s

Total mass, m = 96.5 kg

Mass of the rock, m1 = 0.3 kg

Speed of the rock, v1 = 17.5 m/s

To solve this, we would use the law of conservation of momentum

Momentum before throwing the rock: m*V = 96.5 kg * 0.550 m/s = 53.08 Ns

When the man throws the rock forward

rock:

m1 = 0.300 kg

V1 = 17.5 m/s, in the same direction of the sled with the man

m2 = 96.5 kg - 0.300 kg = 96.2 kg

v2 = ?

Law of conservation of momentum states that the momentum is equal before and after the throw.

momentum before throw = momentum after throw

53.08 = 0.300 * 17.5 + 96.2 * v2

53.08 = 5.25 + 96.2 * v2

v2 = [53.08 - 5.25 ] / 96.2

v2 = 47.83 / 96.2

v2 = 0.497 ~= 0.50 m/s

3 0

3 years ago

How does inertia affect a person who is not wearing a seatbelt during a collision?

ELEN [110]

A person who is not wearing a seatbelt during a collision will be thrown forward because it maintains forward motion

<h3>Further explanation </h3>

In Newton's law, it is stated that if the resultant force acting on an object of magnitude is zero, it can be formulated :

$\large{\boxed{\bold{\Sigma F = 0}}}$

then the object tends to defend itself from its state. So for objects in a state of movement, objects tend to move forever. Likewise, for objects in a state of rest, they tend to remain forever. The tendency of objects like this is called<em> inertia </em>

The size of inertia is proportional to mass, the greater the mass of the object, the greater the inertia of the object.

In objects with mass m that move translatively, the object will maintain its linear velocity

When we are in a vehicle that moves forward, then we will still maintain a state of forwarding motion. If our vehicle stops suddenly, then we keep moving forward so we will be pushed forward. From this point, the use of a safety belt serves to hold back our movements so that there are no fatal accidents or collisions.

<h3>Learn more </h3>

Newton's law of inertia

brainly.com/question/1412777

example of Newton's First Law of inertia

brainly.com/question/1090504

law of motion

brainly.com/question/75210

Keywords: inertia, Newton's First Law

7 0

3 years ago

Read 2 more answers