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rewona [7]
3 years ago
9

The 2.5-Mg van is traveling with a speed of 100 km>h when the brakes are applied and all four wheels lock. If the speed decre

ases to 40 km>h in 5 s, determine the coefficient of kinetic friction between the tires and the road.
Physics
1 answer:
Andrew [12]3 years ago
4 0

Answer:

0.34

Explanation:

2.5 Mg = 2500 kg

The change in speed from 100 km/h to 40 km/h is

\Delta v = 100 - 40 = 60 km/h = 60 * 1000 / (60 * 60) = 16.67 m/s

The deceleration caused by friction force is the change in speed per unit of time

a = \Delta v / \Delta t = 16.67 / 5 = 3.33 m/s^2

Using Newton 2nd law we can calculate the friction force that caused this deceleration:

F = ma = 2500 * 3.33 = 8333 N

Let g = 9.8m/s2. Friction force is the product of normal (gravity) force and friction coefficient

F = mg\mu

8333 = 2500*9.8\mu

\mu = \frac{8333}{2500 * 9.8} = 0.34

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A transformer consisting of two coils wrapped around an iron core is connected to a generator and a resistor (Resistor is connec
V125BC [204]

Answer:

The peak emf of the generator is 40.94 V.

Explanation:

Given that,

Number of turns in primary coil= 11

Number of turns in secondary coil= 18

Peak voltage = 67 V

We nee to calculate the peak emf

Using relation of number of turns and emf

\dfrac{N_{1}}{N_{2}}=\dfrac{E_{1}}{E_{2}}

E_{1}=\dfrac{N_{1}}{N_{2}}\times E_{2}

Where, N₁ = Number of turns in primary coil

N₂ = Number of turns in secondary coil

E₂ = emf across secondary coil

Put the value into the formula

E_{1}=\dfrac{11}{18}\times67

E_{1}=40.94\ V

Hence, The peak emf of the generator is 40.94 V.

4 0
3 years ago
A 75kg man climbs the stairs to the fifth floor of a building. A total hieght of 16m. His potential energy has increased by
yKpoI14uk [10]

Answer:

11760 joules

Explanation:

Given

Mass (m) = 75kg

Height (h) = 16m

Required

Determine the increment in potential energy (PE)

This is calculated as thus:

PE = mgh

Where g = 9.8m/s²

Substitute values for m, g and h.

P.E = 75 * 9.8 * 16

P.E = 11760 joules

8 0
3 years ago
Jeff puts on a leather jacket over his sweater. The sweater becomes negatively charged. Which statements about Jeff’s situation
KiRa [710]

The sweater has a tendency to attract electrons.

The leather jacket has a lower tendency to attract electrons than the sweater.

Explanation:

The sweater and the leather jackets are made up of distinct fabrics that based on their minutest particles called an atom.

An atom is made up of sub-atomic particles of protons, neutrons and electrons.

  • Electrons occupies the bulk volume of the atom and they are easily lost in atoms that are big. They are negatively charged.
  • Protons are positively charged and are very difficult to lose. They occupy the tiny nucleus with neutrons.
  • A body that becomes negatively charged will be said to have a hihg tendency to attract electrons. Normally atoms are electrically neutral. When additional electrons are added to them, they become negatively charged.
  • In this case, the sweater has a high affinity for electrons and it will attract the ones on the leather jacket.
  • The leather jacket has a low tendency to attract electrons than the sweater and it will lose some of its electrons to the sweater.

Learn more:

Protons, neutrons and electrons brainly.com/question/2757829

#learnwithBrainly

3 0
3 years ago
In which regions can the gravitational field strength due to the two planets be zero? Explain.
yan [13]

Answer:

I believe its a and c but my notes are all kinds of messed up so im sorry if its wrong

Explanation:

7 0
3 years ago
Which of the following statements about comets is true? A. Comets rarely fall into an orbit around the Sun. They usually enter t
GREYUIT [131]
<h2>Right answer: Comets have very elliptical orbits that usually take them far beyond the orbit of Pluto, but also take them closer to the Sun than Earth</h2>

Comets are celestial bodies constituted by ice, dust and rocks that orbit around the Sun, after having been altered by the Oort cloud; following different trajectories that can be <u>highly eccentric elliptical</u><u> </u>(periodic trajectories), parabolic or hyperbolic.

One of the main characteristics of a comet is that it travels quite fast, on its way around the Sun and has a long tail. It should be noted that the tails of comets always go in the opposite direction to the Sun (due to the radiation pressure of sunlight).

Therefore, the correct option is C.

4 0
3 years ago
Read 2 more answers
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