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daser333 [38]
2 years ago
15

A man in a lift is moving upwards in a constant speed.the weight of the man is W.Acc

Physics
1 answer:
Nookie1986 [14]2 years ago
3 0

Answer:

Normal force=mg

Explanation:

The reaction force of weight is the normal force.

in order to find the normal for we need to write all the forces and set it equal to the net force:

N-mg=ma (since it is a constant speed the a=0)

N=mg

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5. An object has a momentum of 4,000 kg-m/s and a mass of 115 kg. It crashes into another object that has a mass of 100 kg, and
marishachu [46]

Answer:

D. 18.60

Explanation:

By the law of conservation, the momentum is neither loss nor gained but instead transfered. When they crash into each other, and stick, they combine to create a total mass of 215 kg. Since the momentum is transfered, the two objects, combined, have a total momentum of 4000 kg-m/s. We know that momentum equals mass times velocity. You then divide 4000 by 215 and get approximately 18.6 m/s

4 0
3 years ago
determine the amount of potential energy of a 5.0-N book that is moved to three different shelves on a bookcase . the height of
klasskru [66]
Potential energy<span> is the </span>energy<span> that is stored in an object due to its position relative to some zero position. It is calculated by the expression PE = mgh where mg is the weight of the book and h is the height. It is calculated as follows:

PE = 50(1) = 50 J
</span>PE = 50(1.5) = 75 J
PE = 50(2) = 100 J
7 0
3 years ago
In a region of space where gravitational forces can be neglected, a sphere is accelerated by a uniform light beam of intensity 8
BlackZzzverrR [31]

Answer:

The correct answer is B

Explanation:

To calculate the acceleration we must use Newton's second law

      F = m a

      a = F / m

To calculate the force we use the defined pressure and the radiation pressure for an absorbent surface

       P = I / c        absorbent surface

       P = F / A

       F / A = I / c

       F = I A / c

The area of ​​area of ​​a circle is

      A = π r²

We replace

     F = I π r² / c

Let's calculate

     F = 8.0 10⁻³ π (1.0 10⁻⁶)²/3 10⁸

     F = 8.375 10⁻²³ N

Density is

      ρ = m / V

      m = ρ V

      m = ρ (4/3 π r³)

      m = 4500 (4/3 π (1 10⁻⁶)³)

      m = 1,885 10⁻¹⁴ kg

Let's calculate the acceleration

     a = 8.375 10⁻²³ / 1.885 10⁻¹⁴

     a = 4.44 10⁻⁹ m/s²               absorbent surface

The correct answer is B

4 0
2 years ago
When y⁷ is multiplied by y⁹ the answer is?
Allushta [10]

Answer:

y^16

Explanation:

who need to add the exponents only

7 + 9 = 16

therefore, the answer is y^16

5 0
2 years ago
Look at the equation. What detail is missing? 3 m/s2= (33 m/s - X)/30 S <br>​
Tems11 [23]

Answer:

The starting velocity.

Explanation:

We must understand that this equation comes from the following equation of kinematics.

v_{f}=v_{o}+a*t

where:

Vf = final velocity = 33 [m/s]

Vo = starting velocity [m/s]

a = acceleration = 3 [m/s²]

t = time = 30 [s]

So, these values can be assembly in the following way:

v_{f}=v_{o}+a*t\\a*t=v_{f}-v_{o}\\3=\frac{33-v_{o}}{30}

6 0
3 years ago
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