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yan [13]
1 year ago
10

a person of mass 70 kg is standing in an elevator that is moving downward. the speed decreases uniformly from 4.0 m/s to zero in

2.0 s. what is the normal force acting on the person?
Physics
1 answer:
Anuta_ua [19.1K]1 year ago
6 0

The normal reaction of the boy of mass 70 kg is 826 N.

Let us understand about normal reaction.

The force exerted by a surface on an object in contact with it which prevents the object from passing through the surface is called Normal reaction.

To calculate the normal reaction, we use the formula below.

Formula:

N = mg+m(v-u)/t.......... Equation 1

Where:

N = Normal reaction

m = Mass of the person

g = Acceleration due to gravity

v = Final Velocity

u = Initial velocity

t = Time

From the question,

Given:

m = 70 kg

v = 4 m/s

u = 0 m/s

t = 2 s

g = 9.8 m/s²

Substitute these values into equation 1

N = (70×9.8)+70(4-0)/2

N = 686+140

N = 826 N

Hence, the normal reaction of the boy is 826 N.

Learn more about normal reaction here: brainly.com/question/28788588

#SPJ4

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Answer:

4500 N

Explanation:

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Therefore, a body with mass m, will feel a force f:

f = m v^2/r

Therefore we need another force to keep the body(car) from sliding, this will be given by friction, remember that friction force is given a the normal times a constant of friction mu, that is:

fs = μN = μmg

The car will not slide if     f = fs,   i.e.

fs = μmg =  m v^2/r

That is, the magnitude of the friction force must be (at least) equal to the force due to the centripetal acceleration

fs = (1000 kg)  * (30m/s)^2 / (200 m) = 4500 N

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The six statements below represent Newton's three laws of motion and Kepler's three laws of planetary motion. Match each stateme
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Answer:

1. Force = mass x acceleration - Newton

2. A planet moves faster in the part of its orbit nearer the Sun and slower when farther from the Sun, sweeping out  equal areas in equal times - Kepler

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4. An object moves at constant velocity if there is no net force acting upon it - Newton

5. The orbit of each planet about the Sun is an ellipse with the Sun at one focus  - Kepler.

6. More distant planets orbit the Sun at slower average speeds, obeying the precise mathematical relationship p2-a3 - Kepler.

Explanation:

The three laws of planetary motion formulated by Johannes Kepler or Kepler's laws of planetary motion:

  1. The first law states that the planets move around the Sun in an elliptical orbit with the Sun at one of the foci.
  2. The second law states that the line segment joining a planet to the Sun sweeps out equal areas in equal time.
  3. The third law states that the square of the orbital period (p) of a planet is directly proportional to the cube of the mean distance (a) from the Sun (or semi-major axis of its orbit) i.e., p² is proportional to a³.

The three laws of motion formulated by Sir Isaac Newton or Newton's laws of motion:

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Parasaurolophus was a dinosaur whose distinguishing feature was a hollow crest on the head. The 1.5-m-long hollow tube in the cr
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Answer:

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Explanation:

lets assume speed of sound is 350 m/s.

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