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3 years ago

You drive 6.0 km at 50 km/h and then another 6.0 km at 90 km/h. Your average speed over the 12 km drive will be ____

Physics

1 answer:

Elis [28]3 years ago

5 0

Answer:

The average speed is less than 70 km/h.

(B) is correct option.

Explanation:

Given that,

distance = 6.0 km

Speed = 50 km/h

Speed = 90 km/h

We need to calculate the time in 6.0 km distance

Using formula of time

$t = \dfrac{d}{v}$

Put the value in to the formula

$t=\dfrac{6.0}{50}$

$t=0.12\ hr$

We need to calculate the time in another distance

Using formula of time

$t = \dfrac{d}{v}$

Put the value in to the formula

$t=\dfrac{6.0}{90}$

$t=0.067\ hr$

We need to calculate the average speed

Using formula of average speed

$v=\dfrac{D}{T}$

Where, D = total distance

T = total time

Put the value into the formula

$v=\dfrac{12}{0.12+0.067}$

$v=64.17\ km/hr$

Hence, The average speed is less than 70 km/h.

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A car increases velocity from 30 m/s to 60 m/s in 4 seconds. Calculate the average acceleration of the car over this time.

Lilit [14]

Answer:

B.7.5m/s2

Explanation:

average acceleration=change invelocity/time taken

a=(60-30)/4

=7.5m/s2

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3 years ago

In the following description, QUOTE the portion that addresses weather in the area.

olga nikolaevna [1]

Answer:

Portland normally had rainy, but mild winters. Yesterday it rained 0.75 inches in Portland.

Explanation:

This talks about the weather

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3 years ago

Light does not move infinitely fast but has a finite speed. We normally use ""c"" to indicate the speed of light in science. Wri

Ede4ka [16]

Answer:

6.71 × 10^8 mi/hr

Explanation:

Light is usually defined as an electromagnetic wave that is comprised of a definite wavelength. It is of both types, visible and invisible. The light emitted from a source usually travels at a speed of about 3 × 10^8 meter/sec. This speed of light is commonly represented by the letter 'C'.

To write it in the metric system, it has to be converted into miles/hour.

We know that,

1 minute = 60 seconds

60 minutes = 1 hour

1 kilometer = 1000 meter

1 miles = 1.6 kilometer

Now,

= $\frac{3 \times\ 10^8 meter \times\ 60 sec \times\ 60 min}{1 sec \times\ 1 min \times\ 1 hr}$

= 1.08 × 10^12 m/ hr (meter/hour)

= $\frac{1.08 \times\ 10^{12} meter \times\ 1 km \times\ 1 miles}{1 hr \times\ 1000 meter \times\ 1.6 km}$

= 6.71 × 10^8 mi/hr (miles/hour)

Thus, the value for speed of light (C) in metric unit is 6.71 × 10^8 mi/hr.

5 0

3 years ago

A vertical wire carries a current straight down. To the east of this wire, the magnetic field points: A) toward the east. B) tow

geniusboy [140]

Answer:

option E

Explanation:

the correct answer is option E

the direction of magnetic field will be found out with the help of right hand rule.

Put you palm in the direction of electric field and curl your finger in the direction of magnetic field which east direction.

now, the direction shown by the thumb will be the direction of magnetic field which comes out to be toward South direction.

6 0

3 years ago

Read 2 more answers

1. Is there a relationship between the volume of water displaced and the total volume of the block that has anything to do with

strojnjashka [21]

Answer:

The volume of the block is equal to the volume of water displaced by the block.

Explanation:

Volume refers to the amount of space occupied by a given object (in this case the block). When an object such as the block is immersed in water, it displaces its own volume of water. This volume of water displaced is equal to the volume of the block. Hence we can write;

Final Volume of water - Initial Volume of water= Water Displaced = Volume of the block

Recall that the density of a body is given by;

Density= mass/volume

If we obtain the volume of the block by measuring the volume of water displaced by the block, then we weigh the block using a weighing balance, we can obtain the density of the block easily from the relationship shown above.

8 0

3 years ago