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3 years ago

A train traveling at 50 miles per hour has to slow down to 10 miles per hour in 4 seconds. What is the acceleration

Physics

2 answers:

tester [92]3 years ago

7 0

Acceleration = (change in speed) / (time for the change)

Change in speed = (speed at the end) - (speed at the beginning)

Change in speed = (10 mph) - (50 mph) = -40 mph

Acceleration = (-40 mi/hr) / (4 sec)

Acceleration = -10 mi/hr-sec

To get a more comfortable, familiar unit for the answer . . .

Acceleration =

(-10 mile/hour-second) x (1,609.3 meter/mile) x (1 hour / 3,600 sec)

Acceleration = (-10 x 1,609.3 / 3,600) (mile-meter-hour / hour-sec-mile-sec)

Acceleration = -4.47 m/s²

elena-s [515]3 years ago

3 0

Answer:-10 miles per second

Explanation:

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3 years ago

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A constant voltage of 12.00 V has been observed over a certain time interval across a 1.20 H inductor. The current through the i

kiruha [24]

Answer:

The time is 0.5 sec.

Explanation:

Given that,

Voltage V= 12.00 V

Inductance L= 1.20 H

Current = 3.00 A

Increases rate = 8.00 A

We need to calculate change in current

$\Delta A = 8.00-3.00= 5.00\ A$

We need to calculate the time interval

Using formula of inductor

$V=L\dfrac{\Delta A}{\Delta t}$

$\Delta t =\dfrac{L\Delta A}{V}$

Where, $\Delta A$ = change in current

V = voltage

L = inductance

Put the value into the formula

$\Delta t=\dfrac{1.20\times5.00}{12.00}$

$\Delta t=0.5\ sec$

Hence, The time is 0.5 sec.

5 0

3 years ago

A body weighs 10newton in air and 9.5 in water. How will it weigh in alchohol if density 0.8gcm-³

Katen [24]

Answer:

The weight of object in alcohol is, W₀ = 9.6 N

Explanation:

Given,

The weight of body in air, Wₐ = 10 N

The weight of the body in water, Wₓ = 9.5 N

The density of the alcohol, ρ = 0.8 g/cm³

= 800 kg/m³

The weight of body in water = weight of object in air - weight of water displaced

9.5 N = 10 N - weight of water displaced

Weight of water displaced = 0.5 N

The mass of the displaced water, m = 0.5 / 9.8

= 0.051 kg

Therefore the volume of the water displaced,

V = m / ρ

= 0.051 / 1000

= 5.1 x 10⁻⁵ m³

The volume of water displaced is equal to the volume of alcohol displaced

Therefore, the mass of the alcohol displaced, = V x ρ

= 5.1 x 10⁻⁵ x 800

= 0.0405 kg

The weight of the alcohol displaced, w = 0.0405 x 9.8

= 0.4 N

Therefore,

The weight of body in alcohol = weight of object in air - weight of alcohol displaced

W₀ = W - w

= 10 N - 0.4 N

= 9.6 N

Hence, the weight of object in alcohol is, W₀ = 9.6 N

4 0

3 years ago

A 20 metric ton train moves toward the south at 50 m/s. At what speed must it travel to have four times its original momentum

OverLord2011 [107]

Answer:

200 m/s

Explanation:

as momentum is a product of mass and speed, and mass is not changing, four times the speed will result in four times the momentum.

p = mv

4p = m(4v)

5 0

2 years ago

Lab: Equivalent Resistance of Series and Parallel Circuits

Aleonysh [2.5K]

Answer:

Since there is only one path for the charges to flow through, the current is the same through each resistor. The equivalent resistance of a set of resistors in a series connection is equal to the algebraic sum of the individual resistances.

4 0

3 years ago