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torisob [31]
3 years ago
6

A student pulls horizontally on a block with a spring scale. The block reads 24.5 Newtons before the block starts to move. It re

ads 23.7 Newtons as she pulls the block at a constant velocity. How should she explain this?
Physics
1 answer:
Ahat [919]3 years ago
7 0

Answer:

The coefficient of friction causes the force on the object to be less than its initial reading on the spring scale.

Explanation:

Since the block reads 24.5 N before the block starts to move, this is its weight. Now, when the block starts to move at a constant velocity, it experiences a frictional force which is equal to the force with which the student pulls.

Now, since the velocity is constant so, there is no acceleration and thus, the net force is zero.

Let F = force applied and f = frictional force = μN = μW where μ = coefficient of friction and N = normal force. The normal force also equals the weight of the object W.

Now, since F - f = ma and a = 0 where a = acceleration and m = mass of block,

F - f = m(0) = 0

F - f = 0

F = f

Since the force applied equals the frictional force, we have that

F =  μW and F = 23.7 N and W = 24.5 N

So, 23.7 N = μ(24.5 N)

μ = 23.7 N/24.5 N

μ = 0.97

Since μ = 0.97 < 1, the coefficient of friction causes the force on the object to be less than its initial reading on the spring scale.

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In an interference pattern, the intensity is Group of answer choices smaller in regions of constructive interference than in reg
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Answer:

The same in both the regions of constructive interference and the regions of destructive interference.

Explanation:

Interference is a phenomenon which occurs when two waves meet while moving along the same medium . The amplitude formed as a result of the interference could be greater, lower, or the same amplitude.

Constructive and destructive interference result from the interaction of waves that are correlated or coherent with each other. This is because arose from the same source or they have the same or nearly the same frequency.

The waves being coherent, arising from the same source and having the same frequency explains why it’s the same in both the regions of constructive interference and the regions of destructive interference.

4 0
3 years ago
An air conditioner has a power rating of 3000 W and is used daily. Its electrical
Anarel [89]

Answer:

5.714 hours / day

Explanation:

<u>Calculate the hours used in that week </u>

120000 / 3000 = 120 / 3 = 40 hours a week

<u>Calculate the amount it is used in one day</u>

40 / 7 = 5.71428571 hours or 5.714 hours/day

5 0
2 years ago
Read 2 more answers
A speeder is pulling directly away and increasing his distance from a police car that is moving at 24 m/s with respect to the gr
iogann1982 [59]
2,062,305 2,062,305 <span>2,062,305</span>
8 0
3 years ago
Which is not an example of a scalar?<br><br> a. 2t/s<br> b. 3kg<br> c. 6.2m north<br> d. -100c
xxMikexx [17]
C because I’m a teacher
4 0
3 years ago
A beam of protons is moving toward a target in a particle accelerator. This beam constitutes a current whose value is. (a) How m
Gelneren [198K]

Answer:

a. 5 × 10¹⁹ protons b. 2.05 × 10⁷ °C

Explanation:

Here is the complete question

A beam of protons is moving toward a target in a particle accelerator. This beam constitutes a current whose value is 0.42 A. (a) How many protons strike the target in 19 seconds? (b) Each proton has a kinetic energy of 6.0 x 10-12 J. Suppose the target is a 17-gram block of metal whose specific heat capacity is 860 J/(kg Co), and all the kinetic energy of the protons goes into heating it up. What is the change in temperature of the block at the end of 19 s?

Solution

a.

i = Q/t = ne/t

n = it/e where i = current = 0.42 A, n = number of protons, e = proton charge = 1.602 × 10⁻¹⁹ C and t = time = 19 s

So n = 0.42 A × 19 s/1.602 × 10⁻¹⁹ C

       = 4.98 × 10¹⁹ protons

       ≅ 5 × 10¹⁹ protons

b

The total kinetic energy of the protons = heat change of target

total kinetic energy of the protons = n × kinetic energy per proton

                                                         = 5 × 10¹⁹ protons × 6.0 × 10⁻¹² J per proton

                                                         = 30 × 10⁷ J

heat change of target = Q = mcΔT ⇒ ΔT = Q/mc where m = mass of block = 17 g = 0.017 kg and c = specific heat capacity = 860 J/(kg °C)

ΔT = Q/mc = 30 × 10⁷ J/0.017 kg × 860 J/(kg °C)

     = 30 × 10⁷/14.62

     = 2.05 × 10⁷ °C

5 0
3 years ago
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