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2 years ago

7

Does kinetic energy stay the same at all heights? pls help I have 12 minutes to finish the project and the teacher won't help me

:(

1 answer:

Alex Ar [27]2 years ago

7 0

Answer:

Kinetic energy does not stay the same at all heights

Explanation:

Well as the height and wind increase so does the kinetic energy it's like when you fall as you are about to hit the floor you speed increases

HOPE THIS HELPS YA :)

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mestny [16]

Answer:

kftisgkstisirstizurzursrus

3 0

3 years ago

1. The illuminance on a surface is 6 lux and the surface is 4 meters from the light source. What is the intensity of the source?

Crank

<u>Answer</u>

1) A. 96 Candelas

2) A. Both of these types of lenses have the ability to produce upright images.

3) C. 5 meters

<u>Explanation</u>

Q1

The formula for calculation the luminous intensity is;

Luminous intensity = illuminance × square radius

Lv = Ev × r²

= 6 × 4²

= 6 × 16

= 96 Candelabra

Q2

For converging lenses, an upright image is formed when the object is between the lens and the principal focus while a diverging lens always forms and upright image.

A. Both of these types of lenses have the ability to produce upright images.

Q3

Luminous intensity = illuminance × square radius

square radius = Luminous intensity/ illuminance

r² = 100/4

= 25

r = √25

= 5 m

5 0

3 years ago

Read 2 more answers

Two people stand facing each other at roller skating rink then push off each other

9966 [12]

a) 0 kg m/s

b) 0 kg m/s

c) +3 m/s

d) 60 N

Explanation:

a)

The momentum of an object is a vector quantity given by:

$p=mv$

where

m is the mass of the object

v is the velocity of the object

In this problem, we have a system of two people, so the total momentum will be the sum of the individual momenta of the two people:

$p=p_1 + p_2$

Which can be rewritten as

$p=m_1 u_1 + m_2 u_2$

where $m_1,m_2$ are the masses of the two people and $u_1,u_2$ their initial velocities.

However, the two people are initially at rest, so

$u_1 = 0\\u_2 = 0$

Therefore the total momentum is

$p=0+0=0$

b)

The principle of conservation of momentum states that when there are no external forces acting on a system, the total momentum of the system is conserved, so we can write:

$p_i = p_f$

where

$p_i$ is the total momentum of the system before

$p_f$ is the total momentum of the system after

In this problem,

$p_i = 0$

As we calculated in part a: this is because the total momentum of the two people before they push off each other is zero.

Therefore, according to the law of conservation of momentum,

$p_f = p_i = 0$

So the total momentum is zero also after they push off each other.

c)

The total momentum of the girl and the boy after they push off each other can be written as:

$p_f = m_1 v_1 + m_2 v_2$ (1)

where:

$m_1 = 30 kg$ is the mass of the girl

$v_1 = -5 m/s$ is her velocity (she moves backward, so the negative sign)

$m_2 = 50 kg$ is the mass of the boy

$v_2$ is the velocity of the boy

As calculated in part b), we also know that the total momentum of the girl and the boy is

$p_f = 0$ (2)

By combining eq(1) and eq(2) we get

$0=m_1 v_1 + m_2 v_2$

And solving for v2 we find the velocity of the boy:

$v_2=-\frac{m_1 v_1}{m_2}=-\frac{(30)(-5)}{50}=+3 m/s$

and the positive sign means he is moving forward.

d)

We can solve this part by applying the impulse theorem, which states that the change in momentum of an object is equal to the product between the force applied on it and the duration of the collision:

$\Delta p = F\Delta t$

where

$\Delta p$ is the change in momentum

F is the force

$\Delta t$ is the time during which the force is applied

In this problem:

$\Delta t = 2.5 s$

For the boy, the change in momentum is:

$\Delta p = m_2 (v_2 - u_2)$

And since

$m_2 = 50 kg\\u_2 = 0 m/s\\v_2 = 3 m/s$

We have

$\Delta p = (50)(3-0)=150 kg m/s$

So, the force exerted between the boy and the girl is:

$F=\frac{\Delta p}{\Delta t}=\frac{150}{2.5}=60 N$

8 0

3 years ago

What explains the dramatically different magnitudes of accelerations that result when a mosquito collides head on with a moving

Evgen [1.6K]

Answer:

Mass of the vehicle and small bug.

Explanation:

By Newton's third law, force on bug and vehicle will be same when they collide with each other irrespective of their masses.

But according to Newton's second law, force is mass times acceleration. Since the force on each mass is same, the smaller mass will accelerate more and the heavier mass will accelerate less for the same force.
Therefore the acceleration of bug will be very greater than vehicle as the mass of the bug is very small as compared to vehicle.

Learn more about Newton's law.

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#SPJ10

7 0

2 years ago

PLS HELPPP!! ITS DUE TODAY!

Andrews [41]

A is an example of physical change

3 0

3 years ago