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IrinaK [193]
3 years ago
12

An object A with a kinetic energy of 800 joules moving horizontally is subjected to a force of 100 Newtons, which is the opposit

e of motion as it moves from point X to point Y. XY distance is 2 m. What is the energy of A at point Y?
Physics
1 answer:
sveta [45]3 years ago
7 0

Answer:

d = 8 [m]

Explanation:

To solve this problem we must use the principle of conservation of energy, where the mechanical energy in a state plus the work done on the body, must be equal to the mechanical energy in the state Y. This can be easily represented in the following equation.

E_{x}+W_{x-y}=E_{y}

where:

Ex = Mechanical energy in X [J]

Wx-y = Work among states x and y [J]

Ey = Mechanical energy in Y [J].

The key to being able to understand this problem is that in state X, we only have kinetic energy, while the energy in state Y is equal to zero (there is no movement). The work is equal to the product of force by distance, as work acts in the opposite direction to movement, this has a negative sign.

800 - F*d = 0\\100*d = 800\\d = 800/100\\d = 8 [m]

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Two spheres are cut from a certain uniform rock. One has radius 4.50 cm. The mass of the other is five times greater. Find its r
Sonja [21]
Vol of sphere = 4/3 pi r^2.density of sphere = mass/volume.mass = densityxvolumesphere 1. mass = density x 4/3 pi 4.5^2sphere 2 5mass = density x 4/3 pi r^25=4/3 pi r^2 divided by 4/3 pi 4.5^25=r^2 divided by  4.5^25x4.5^2=r^2root(5x4.5^2)=r4.5 root 5 = r
4 0
2 years ago
Read 2 more answers
With the frequency set at the mid-point of the slider and the amplitude set at the mid-point of the slider, approximately how ma
Alenkinab [10]

Answer:

The wavelength stays the same.

Explanation:

When the amplitude is increased, the wavelength stays the same.

Here the wavelength doesn't depend upon the amplitude.

4 0
3 years ago
A 1300-N crate rests on the floor. How much work is required to move it at constant speed (a)
kherson [118]

a) The work done is 920 J

b) The work done is 5200 J

Explanation:

a)

In this first part of the problem, the crate is moved horizontally at constant speed.

The work required in this case is given by

W=Fd cos \theta

where

F is the magnitude of the force applied

d is the displacement of the crate

\theta is the angle between the direction of the force and of the displacement

Here the crate is moved at constant speed: this means that the acceleration of the crate is zero, and so according to Newton's second law, the net force on the crate is zero: this means that the force applied, F, must be equal to the force of friction (but in opposite direction), so

F = 230 N

The displacement is

d = 4.0 m

And the angle is \theta=0^{\circ}, since the force is applied horizontally. Therefore, the work done is

W=(230)(4.0)(cos 0^{\circ})=920 J

b)

In this case, the crate is moved vertically. The force that must be applied to lift the crate must be equal to the weight of the crate (in order to move it a constant speed), therefore

F = W = 1300 N

The displacement this time is again

d = 4.0 m

And the angle is \theta=0^{\circ}, since the force is applied vertically, and the crate is moved also vertically. Therefore, the work done on the crate this time is

W=(1300)(4.0)(cos 0^{\circ})=5200 J

Learn more about work:

brainly.com/question/6763771

brainly.com/question/6443626

#LearnwithBrainly

4 0
3 years ago
A toy plane is flying in a horizontal circle by being attached to a 0.75 meter string. The plane has a mass of 101.7 grams and m
nadezda [96]

Answer:

F = 2,894 N

Explanation:

For this exercise let's use Newton's second law

      F = m a

The acceleration is centripetal

     a = v² / r

Angular and linear variables are related.

     v = w r

Let's replace

     F = m w² r

The radius r and the length of the rope is related

    cos is = r / L

    r = L cos tea

Let's replace

    F = m w² L cos θ

Let's reduce the magnitudes to the SI system

     m = 101.7 g (1 kg / 1000g) = 0.1017 kg

      θ = 5 rev (2π rad / rev) = 31,416 rad

     w =  θ / t

     w = 31.416 / 5.1

     w = 6.16 rad / s

     F = 0.1017 6.16² 0.75 cos  θ

     F = 2,894 cos  θ

The maximum value of F is for  θ equal to zero

     F = 2,894 N

7 0
3 years ago
I need help on all of this
wel

dude is -2m/s, ...ettte is +2m/s

pos vel is when dudette, eg, is going in increasing x, in this case.

neg vel  is when dudette, eg, is going in decreasing x, in this case. ie she turns round and runs

zero vel is zero speed. dudette standing still

positive vel neg pos top dia

no

yes

yes

yes

yes

yes

all yes looks like ...




4 0
3 years ago
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