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JulsSmile [24]
2 years ago
5

If a force of 30N is applied to an object of mass 8kg which is kept on a surface, it achieves an acceleration of 3m/s. What is t

he frictional force in Newton between the object and the surface?
a) 0
b) 6
c) 24
d) 54
​
Physics
1 answer:
Eduardwww [97]2 years ago
3 0

By Newton's second law, the net force on the object acting parallel to the surface is

∑ F = F[applied] - F[friction] = (8k g) (3 m/s²)

If F[applied] = 30 N, then

30 N - F[friction] = 24 N   ⇒   F[friction] = 6 N

so the answer is B.

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A car drives at steady speed around a perfectly circular track.
gayaneshka [121]

Answer:

e. Both the acceleration and net force on the car point inward.

Explanation:

If no net force acts on the car, the car must drive in a straight line, at constant speed.

As the acceleration is defined as the rate of change of the velocity vector, this means that it can produce either a change in the magnitude of the velocity (the speed) or in the direction.

In order to the car can follow a circular trajectory, it must be subjected to an acceleration, that must go inward, trying to take the car towards the center of the circle.

The net force that causes this acceleration, aims inward, and is called the centripetal force.

It is not a different type of force, it can be a friction force, a tension force, a normal force, etc., as needed.

6 0
3 years ago
An infinite line of charge with linear density λ1 = 6 μC/m is positioned along the axis of a thick insulating shell of inner rad
Anna11 [10]

Answer: λ2= 2.34 * 10^-6 C/m

Explanation: In order to calculate the value of the  linear charge density of the insulating shell we have to multiply ρ* Volume of the hollow cylinder, so

Volume of cylinder:2*π*b*L *(b-a)  where (b-a) is the thickness, then

λ2=Q/L = 634 *10^-6 C/m^3* 2*π*0.042 m*(0.042-0.26)== 2.34 μ C/m

5 0
3 years ago
All you have to do is find the description for a b c and d words and find the meaning 8 9 10 11 and 12
insens350 [35]
A-11 polar easterlies
b-8 winds blowing between the equator and 30° N and south
c-10
d-9
4 0
3 years ago
(a) How many kilograms of water must evaporate from a 60.0-kg woman to lower their body temperature by 0.750ºC?
Mrrafil [7]

Answer:

69.69 g

Explanation:

Evaporation of water will take out latent heat of vaporization.  Let the mass of water be m and latent heat of vaporization of water be 2260000 J per kg

Heat taken up by evaporating water

= 2260000 x m J

Heat lost by body

= mass x specific heat of body x drop in temperature

60 x 3500 x .750  ( specific heat of human body is 3.5 kJ/kg.k)

= 157500 J

Heat loss = heat gain

2260000 m= 157500

m = .06969 kg

= 69.69 g

5 0
3 years ago
You are at the controls of a particle accelerator, sending a beam of 2.10×107 m/s protons (mass m) at a gas target of an unknown
Kipish [7]

Answer:

a

The mass is  m_2 =21.75*10^{-27} \ kg

b

The velocity is  v_2 = 3.0*10^{6} m/s

Explanation:

From the question we are told that

     The speed of the protons is  u_1 =  2.10*10^{7} m/s

     The mass of the protons is  m

     The speed of the rebounding protons are v_1 =  -1.80 * 10^{7} \ m/s

The negative sign shows that it is moving in the opposite direction

     

Now according to the law of energy conservation mass of one nucleus of the unknown element. is mathematically represented as

        m_2 = [\frac{u_1 -v_1}{u_1 + v_1} ] m_1

Where m_1 is the mass of a single proton

          So substituting values

       m_2 = \frac{2.10 *10^{7} - (-1.80 *10^{7})} {(2.10 *10^7) + (-1.80 *10^{7})} m_1

        m_2 =13 m_1

The mass of on proton is  m_1 = 1.673 * 10^{-27} \ kg

So     m_2 =13 ( 1.673 * 10^{-27} )

        m_2 =21.75*10^{-27} \ kg

Now according to the law of linear momentum conservation the speed of the unknown nucleus immediately after such a collision is mathematically evaluated as

      m_1 u_1 + m_2u_2 = m_1 v_1 + m_2v_2

Now  u_2 because before collision the the nucleus was at rest

So

        m_1 u_1 =  m_1 v_1 + m_2v_2

=>    v_2 =  \frac{m_1(u_1 -v_1)}{m_2}

Recall that m_2 =13 m_1

So

       v_2 =  \frac{m_1(u_1 -v_1)}{13m_1}

=>         v_2 =  \frac{(u_1 -v_1)}{13}

substituting values

              v_2 =  \frac{( 2.10*10^{7} -(-1.80 *10^{7}))}{13}

              v_2 = 3.0*10^{6} m/s

   

7 0
3 years ago
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