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3 years ago

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A car of mass 960.0 kg accelerates away from an intersection on a horizontal road. When the car speed is 51.1 km/hr (14.2 m/s),

the net power which the engine supplies is 3700.0 W (in addition to the extra power required to make up for air resistance and friction). Calculate the acceleration of the car at that time.

1 answer:

blagie [28]3 years ago

5 0

Answer:

$0.27 m/s^2$

Explanation:

The power supplied by the engine is given by

P = Fv

where

F is the force applied

v is the velocity of the car

Here we have

P = 3700 W

v = 14.2 m/s

So we can solve the equation to find the average force:

$F=\frac{P}{v}=\frac{3700 W}{14.2 m/s}=260.6 N$

The net force applied on the car is also equal to

F = ma

where

m = 960.0 kg is the mass of the car

a is the acceleration

Re-arranging the equation, we find the acceleration:

$a=\frac{F}{m}=\frac{260.6 N}{960.0 kg}=0.27 m/s^2$

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A sprinter accelerates from rest to 10.0 m/s in 1.28 s . Part A Part complete What is her acceleration in m/s2? a a = 7.81 m/s2

Mashutka [201]

Explanation:

It is given that,

Initial speed of sprinter, u = 0

Final speed of sprinter, v = 10 m/s

Time taken, t = 1.28 s

a. We need to find the acceleration of sprinter. It can be calculated using first equation of motion as :

$a=\dfrac{v-u}{t}$

$a=\dfrac{10\ m/s}{1.28\ s}$

$a=7.81\ m/s^2$

b. Final speed of the sprinter, v = 36 km/h

Time, t = 0.000355 h

Acceleration, $a=\dfrac{36}{0.000355}$

$a=101408.45\ km/h^2$

Hence, this is the required solution.

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4 years ago

Why might an electromagnet be used to pick up old cars in junk yards?

s344n2d4d5 [400]

I think the correct answer would be that because electromagnets are powerful and can be turned off and on anytime. Electromagnet is a magnet in which the magnetic field is made by the electric current that is induced to the system.

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3 years ago

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The nonreflective coating on a camera lens with an index of refraction of 1.29 is designed to minimize the reflection of 634-nm

eimsori [14]

Answer:

minimum thickness of the coating = 122.868 nm

Explanation:

Given data

lens index of refraction = 1.29

wavelength = 634 nm

glass index of refraction = 1.53

to find out

minimum thickness of the coating

solution

we have given non reflective coating

so

we know that minimum thickness of the coating formula

minimum thickness of the coating = Wavelength / 4n

here n is coating index of refraction

so put here both value to get thickness

minimum thickness of the coating = Wavelength / 4n

minimum thickness of the coating = 634 / 4 ( 1.29 )

so minimum thickness of the coating = 122.868 nm

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3 years ago

The wavelength of light is 5000 angstrom. Express it in nm and m.

Ierofanga [76]

Answer:

1 angstrom = 0.1nm

5000 angstrom = 5000/1 × 0.1nm

<h3>= 500nm</h3>

$1 \: angstrom = 1 \times {10}^{ - 10} m$

5000 angstrom = 5000 × 1 × 10^-10

<h3>= 5 × 10^-7 m</h3>

Hope this helps you

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3 years ago

A circuit consists of a battery connected to three resistors (65 ω, 25ω, and 170ω) in parallel. the total current through the re

White raven [17]

A. To find the total emf of the battery, just remember that in a parallel circuit, the voltage is the same throughout the circuit. So you can get the total voltage of the circuit by using Ohm's Law.

$I= \frac{V}{R}$

Where:
I = current (A)
V = Voltage (V) (emf)
R = Resitance (Ω)

Now you can derive the formula of Voltage by transposing the Resistance to the other side of the equation to isolate Voltage. The formula you will now use will be:
$V = IR$

However, you cannot solve this yet because the resistance you need is the total resistance in the circuit. To do this, you need to get the total resistance in this parallel circuit and the formula would be:

$\frac{1}{R_{T}} = \frac{1}{R_{1}}+ \frac{1}{R_{2}}+ \frac{1}{R_{3}}...+ \frac{1}{R_{n}}$

You have three resistors with the following resistance:
65Ω, 25Ω and 170Ω
$\frac{1}{R_{T}} = \frac{1}{R_{1}}+ \frac{1}{R_{2}}+ \frac{1}{R_{3}}...+ \frac{1}{R_{n}}$

$\frac{1}{R_{T}} = \frac{1}{R_{65}}+ \frac{1}{R_{25}}+ \frac{1}{R_{170}}$

$\frac{1}{R_{T}} =0.0153+0.04+0.006+0.0059$
$\frac{1}{R_{T}} =0.0613$

Get the reciprocal of both sides and divide:

$R_{T} = \frac{1}{0.0613} =16.32$

The total resistance then is 16.32Ω

Now that you have the total resistance, you can solve for the total voltage:
$V = IR$
$V = (1.8)(16.32)$
$V = 29.376V$

The emf of the battery is 29.376V

B. To find the resistance in each resistor, just apply Ohm's law again. In a parallel circuit, the voltage is the same, but the current that runs through it is different for each resistor. Now just solve for the current of each using the same voltage.

Resistor 1: 65Ω
$I= \frac{V}{R}$
$I= \frac{29.376}{65}$
$I= 0.45A$

The current flowing through resistor 1 with a resistance of 65Ω is 0.45A.

Resistor 2: 25Ω
$I= \frac{V}{R}$
$I= \frac{29.376}{25}$
$I= 1.18A$
The current flowing through resistor 2 with a resistance of 25Ω is 1.18A.

Resistor 3: 170Ω
$I= \frac{V}{R}$
$I= \frac{29.376}{170}$
$I= 0.17A$

The current flowing through resistor 3 with a resistance of 170Ω is 0.17A.

If you add up all their current it confirms the given that the total current running through all of them is 1.8A.

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3 years ago