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3 years ago

5

A car slams on its brakes creating an acceleration of -4.7 m/s^2. It comes to rest after traveling a distance of 235 m. What was

its velocity before it began to accelerate?

1 answer:

Sever21 [200]3 years ago

7 0

Answer:

Explanation:

v² = u² + 2as

0² = u² + 2(-4.7)(235)

u² = 2209

u = 47 m/s

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A mass of 10.0 kg is in a gravitational field of 3.50 N/kg. What force acts on the mass?

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Answer:

Force=35 N

Explanation:

Given data

mass m=10.0 kg

Gravitational field E=3.50 N/kg

To find

Force

Solution

From definition of gravitational field intensity.

$E_{gravitational-field }=\frac{Force}{mass}\\ E=F/m\\F=mE\\F=(10.0 kg)*(3.50 N/kg)\\F=35N$

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Decrease the charge of one of the particles

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A diver springs upward from a board that is 4.40 m above the water. At the instant she contacts the water her speed is 13.5 m/s

Yakvenalex [24]

The diver has the initial velocity, both (a) magnitude is 9.8 m/s and (b) direction is 73.5°.

<h3>What is free falling?</h3>

When an object is released from rest in free air considering no friction, the motion is depend only on the acceleration due to gravity, g.

If we drop an object of mass m near the Earth surface from a height h, it has initial mechanical energy(P.E)

U =mgh

When the object strikes the ground, all the potential energy converted into kinetic energy.

K.E = 1/2mv²

where v is the speed just before hitting the ground.

A diver springs upward from a board that is 4.40 m above the water. At the instant, she contacts the water her speed is 13.5 m/s and her body makes an angle of 78.1 ° with respect to the horizontal surface of the water.

(a)

From energy conservation principle, initial and final mechanical energy are equal.

1/2mu² + mgh = 1/2mv²

where, u is the initial velocity of the diver.

u = sq rt (v² - 2gh)

u = sq rt (13.5² - 2x9.81x4.4)

u = 9.798 m/s or 9.8 m/s

Thus, the velocity of the diver is 9.8 m/s.

(b)

The horizontal component of velocity will remain constant.

The horizontal component of acceleration is zero.

Then,

ucosθ = vcosΦ

θ = cos⁻¹ [ (13.5 x cos 78.1)/9.8 ]

θ = 73.5°

Thus, the direction of velocity is 73.5°.

Learn more about free falling.

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2 years ago

The Otto-cycle engine in a Mercedes-Benz SLK230 has a compression ratio of 8.8. What is the ideal efficiency of the engine? Use

vodomira [7]

Answer:

e=58%

Explanation:

Given data

The Otto-cycle engine in a Mercedes-Benz SLK230 has a compression ratio of 8.8.

Solution

We want to calculate the ideal efficiency of the engine when ratio of heat capacity for gas used γ=1.40. Ideal efficiency (e) of the Otto cycle given by:

$e=1-(\frac{1}{r^{Y-1} } )\\$

Substitute the given values to find efficiency e

$e=1-\frac{1}{8.8^{1.4-1} } \\e=0.58\\$

e=58%

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3 years ago