What name is given to the property of an object to resist changes in motion

2. Suppose one of your classmates says “The net force on an airplane is zero, therefore

poizon [28]

This is a false statement. Newton's first law says that if the net force on an object is zero, the object stays in UNIFORM MOTION. That means it keeps moving at a constant speed, in a straight line. It can certainly have some speed, in some direction, but without any net force, they CAN'T CHANGE.

5 0

4 years ago

What does it mean for a substance to have a high reactivity?

BaLLatris [955]

Reactivity is the tendency of a substance to undergo chemical reaction, either by itself or with other materials, and to release energy.

7 0

4 years ago

A marathon runner completes a 42.238 km course in 2 h, 31 min, and 46 s . There is an uncertainty of 29 m in the distance run an

icang [17]

Answer:

The percentage uncertainty in the average speed is 0.10% (2 sig. fig.)

Explanation:

Consider the formula for average speed $\bar{v}$ .

$\displaystyle \bar{v} = \frac{s}{t}$ ,

where

$s$ is the total distance, and
$t$ is the time taken.

The percentage uncertainty of a fraction is the sum of percentage uncertainties in

the numerator, and
the denominator.

What are the percentage uncertainties in $s$ and $t$ in this question?

The unit of the absolute uncertainty in $s$ is meters. Thus, convert the unit of $s$ to meters:

$s = \rm 42.238\;km = 42.238\times 10^{3}\;m$ .

$\begin{aligned}\displaystyle \text{Percentage Uncertainty in }s &= \frac{\text{Absolute Uncertainty in } s}{\text{Measured Value of }s}\times 100\% \\ &=\rm\frac{29\; m}{42.238\times 10^{3}\;m}\times 100\%\\ &= 0.0687\%\end{aligned}$ .

The unit of the absolute uncertainty in $t$ is seconds. Convert the unit of $t$ to seconds:

$t = \rm 2\times 3600 + 31\times 60 + 46 = 9106\;s$

Similarly,

$\begin{aligned}\displaystyle \rm \text{Percentage Uncertainty in }t &= \frac{\text{Absolute Uncertainty in }t}{\text{Measured Value of }t}\times 100\% \\ &=\rm\frac{46\; s}{9106\;s}\times 100\%\\ &= 0.0329\%\end{aligned}$ .

The average speed $\bar{v}$ here is a fraction of $s$ and $t$ . Both $s$ and $t$ come with uncertainty. The percentage uncertainty in $\bar{v}$ will be the sum of percentage uncertainties in $s$ and $t$ . That is:

$\text{Percentage Uncertainty in }\bar{v}\\=(\text{Percentage Uncertainty in } s) + (\text{Percentage Uncertainty in } t)\\ = 0.0687\% + 0.0329\%\\ = 0.010\%$ .

Generally, keep

two significant figures for percentage uncertainties that are less than 2%, and
one for those that are greater than 2%.

The percentage uncertainty in $\bar{v}$ here is less than 2%. Thus, keep two significant figures. However, keep more significant figures than that in calculations to make sure that the final result is accurate.

3 0

4 years ago

In which of the following conditions would there be the most resistance?

Natasha2012 [34]

Answer:

A) A warm wire

Explanation:

A warm wire has the most resistance. Heating the metal wire causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance. Heating the wire increases resistivity.

8 0

3 years ago

Can someone help me its A,B,C,D

Tatiana [17]

I think C i’m so sorry if i’m wrong tho.

6 0

3 years ago