Does a physical change affect the identity of a substance? Does a chemical change affect the identity of a substance?

A general contractor drives 5 miles to the hardware store in 10 minutes. He shops for needed tools for 30 minutes, then drives t

Alex17521 [72]

Given parameters:

Distance to hardware shop = 5 miles

Time to reach hardware shop = 10 minutes

Time spent at the shop = 30 minutes

Average speed to customer home = 45 mph

Time taken for the travel = 20 minutes

Unknown:

Average speed of the contractor = ?

Solution:

Average speed is the total distance covered divided by the total time taken.

Average speed = $\frac{total distance}{total time taken}$

total distance = distance to hardware shop + distance to customer's home

We do not know the distance to customer's home but we have been given the speed and time, so we can find the distance.

Distance = speed x time

Convert the time to hrs and solve;

60 minutes = 1 hr

20 minutes = $\frac{20}{60} hr$ = $\frac{1}{3} hr$

So, Distance = 45mph x $\frac{1}{3} hr$ = 15miles

Now;

Total distance = 5 + 15 = 20miles

Total time = time to reach hardware shop + time to reach customer's house

= 10 + 20

= 30 minutes

Convert the time from minutes to hrs;

60 minutes = 1hr

30 minutes = $\frac{30}{60}$ = 0.5hr

So;

Average speed = $\frac{20}{0.5}$ = 40mph

The average speed is 40mph

3 0

3 years ago

Determine the values of m and n when the following average distance from the Sun to the Earth is written in scientific notation:

Leviafan [203]

Answer:

$150000000000\ m=1.5\times 10^{11}\ m$

Explanation:

A number can be written in the form of :

$N=m\times 10^n$

Where

m is the real number

n is any integer

In this case, the average distance from the Sun to the Earth is given,

d = 150000000000 meters

There are 10 zeroes in this number. We need to write this number in scientific notation. It is given by :

$d=1.5\times 10^{11}\ m$

So, the average distance from the Sun to the Earth is $d=1.5\times 10^{11}\ m$ . Hence, this is the required solution.

3 0

3 years ago

The graph below is called a heating curve. It shows how water changes from one state of matter to another based on temperature a

Neporo4naja [7]

Explanation :

The heating curve shows how water changes from one state of matter to another based on temperature and the addition or removal of heat over time.

Initially, ice is heated until its temperature reaches $0^0\ C$ and changes to liquid state.

From the attached graph it is clear that until $100^0\ C$ the temperature will rise steadily. Here, the liquid begins to vaporize. Vaporization is the state of matter at which liquid state changes to the gaseous state.

So, E is the point which shows the gaseous state.

4 0

3 years ago

Read 2 more answers

Which instrument is used to measure depth of ocean ?

skelet666 [1.2K]

Echo sounding is a type of SONAR used to determine the depth of water by transmitting sound pulses into water. The time interval between emission and return of a pulse is recorded, which is used to determine the depth of water along with the speed of sound in water at the time.

5 0

3 years ago

What is meant by the statement,the linear expansivity of copper is 0.000017k

Aliun [14]

Answer:

The change in length per unit length per degree rise in temperature of copper is 0.000017k

Explanation:

Given that :

The linear expansivity of copper is 0.000017k. This simply means that ; for a given copper length, the length of such copper will increase by 0.000017k for every degree rose in temperature of the copper rod.

Therefore, the change in length per unit length per degree rise in temperature (k) is 0.000017

4 0

2 years ago