Ask question

Ask question

All categories

3 years ago

6

The speed limit on a highway is 65 miles per hour. a driver wants to travel 487 miles along the highway in the next 9.8 hours. w

hat is the longest span of rest time available to the driver to complete this journey without ever exceeding the speed limit?

1 answer:

topjm [15]3 years ago

7 0

1) 487 miles / 65 miles per hour = 7.5h at max speed
2) 9.8h - 7.5h = 2.3h rest time avaliable

You might be interested in

Voltage needed to raise current to 3.75a using 20,20,200 resistor set

Varvara68 [4.7K]

<u>Answer:</u> The voltage needed is 35.7 V

<u>Explanation:</u>

Assuming that the resistors are arranged in parallel combination.

For the resistors arranged in parallel combination:

$\frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$

We are given:

$R_1=20\Omega\\R_2=20\Omega\\R_3=200\Omega$

Using above equation, we get:

$\frac{1}{R}=\frac{1}{20}+\frac{1}{20}+\frac{1}{200}\\\\\frac{1}{R}=\frac{10+10+1}{200}\\\\R=\frac{200}{21}=9.52\Omega$

Calculating the voltage by using Ohm's law:

$V=IR$ .....(1)

where,

V = voltage applied

I = Current = 3.75 A

R = Resistance = $9.52\Omega$

Putting values in equation 1, we get:

$V=3.75\times 9.52\\\\V=35.7V$

Hence, the voltage needed is 35.7 V

7 0

3 years ago

Read 2 more answers

An electromagnet is strong enough to lift 200 kg of mass. If you double the number of turns of wire around the core and triple t

VLD [36.1K]

Answer:1200 kg

Explanation:

Given

Electromagnet can lift a mass of $200\ kg$

Magnetic force necessary to hold mass is proportional to Magnetic field

and magnetic field (B) is proportional to NIA

where N=no of turns

I=current in the magnet

A=area of cross-section

When we double the no of turns and triple the current then

N becomes 2 N

I becomes 3 I

therefore magnetic field becomes 6 times

Thus magnetic force becomes 6 times and we can say that electromagnet can hold the 6 times of given weight

i.e. $6\times 200=1200\ kg$

4 0

3 years ago

It has been suggested that a heat engine could be developed that made use of the fact that the temperature several hundred meter

lesantik [10]

Answer:

efficiency = 5.4%

Explanation:

Efficiency of heat engine is given as

$\eta = \frac{W}{Q_{in}}$

now we will have

$W = Q_1 - Q_2$

so we will have

$\eta = 1 - \frac{Q_2}{Q_1}$

now we know that

$\frac{Q_2}{Q_1} = \frac{T_2}{T_1}$

so we have

$\eta = 1 - \frac{T_2}{T_1}$

$\eta = 1 - \frac{273+6}{273+22}$

$\eta = 0.054$

so efficiency is 5.4%

8 0

3 years ago

Which statement describes Newton's law of universal gravitation?

Ray Of Light [21]

Last one: Every object in the universe attracts every other object

8 0

3 years ago

Calculate the force between two touching grape fruits each with a radius of 0.08 meters and a mass of 0.45 kilograms

Volgvan

Hope it cleared your doubt.

3 0

3 years ago

Read 2 more answers