What is the speed of a vehicle that travels 80 meters in 2 seconds?

What is the resistivity of a wire of 1.3 mm diameter, 2.3 m length, and 61 ms resistance. Number Units The number of significant

kakasveta [241]

Answer:

$\rho = 3.68 *10^{-8} Ω. m$

Explanation:

The resistance is given as

$R = \frac{\rho L}{A}$

Where A IS Cross sectional area of wire $= \pi r^{2}$

therefore resistivity \rho can be wrtten as

$\rho = \frac{\pi Rd^{2}}{4L}$

Putting all value to get resistivity value $\rho =\frac{\pi* 61*10^{-3}* (1.33*10^{-3})^{2}}{4*2.3}$

$\rho = 3.68 *10^{-8} Ω. m$

3 0

4 years ago

A bullet of mass 6.20 10-3 kg, moving at 1320 m/s impacts a tree stump and penetrates 11.00 cm into the wood before coming to re

sladkih [1.3K]

Answer:

F = -49.1 10³ N

Explanation:

Let's use the kinematics to find the acceleration the acceleration of the bullet that they tell us is constant

$v_{f}$ ² = v₀² + 2 a x

Since the bullet is at rest, the final speed is zero

x = 11.00 cm (1 m / 100 cm) = 0.110 m

0 = v₀² + 2 a x

a = -v₀² / 2 x

a = -1320²/(2 0.110)

a = -7.92 10⁶ m / s²

With Newton's second law we find the force

F = m a

F = 6.20 10⁻³ (-7.92 10⁶)

F = -49.1 10³ N

The sign means that it is the force that the tree exerts to stop the bullet

8 0

3 years ago

What volume (in liters) of gasoline has a total heat of combustion equal to the energy obtained in part (a)? (see section 17.6;

antiseptic1488 [7]

<h3><u>Answer;</u></h3>

volume = 6.3 × 10^-2 L

<h3><u>Explanation</u>;</h3>

Volume = mass/density

Mass = 0.0565 Kg,

Density = 900 kg/m³

= 0.0565 kg/ 900 kg /m³

= 6.3 × 10^-5 M³

but; 1000 L = 1 m³

Hence, <u>volume = 6.3 × 10^-2 L</u>

8 0

3 years ago

A machine is designed to fill jars with 16 ounces of coffee. A consumer suspects that the machine is not filling the jars comple

babunello [35]

Answer:

a) Null hypothesis: $\mu \geq 16$

Alternative hypothesis : $\mu$

b) $t=\frac{15.6-16}{\frac{0.3}{\sqrt{8}}}=-3.77$

$p_v =P(t_{(7)}$

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

c) We can conclude that the mean is significantly less than 16 ounces at 10% of significance. so then the consumer suspect is correct.

Explanation:

Data given and notation

$\bar X=15.6$ represent the mean for the sample

$s=0.3$ represent the sample standard deviation

$n=8$ sample size

$\mu_o =16$ represent the value that we want to test

$\alpha=0.1$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

Is a one tailed left test.

What are H0 and Ha for this study?

Null hypothesis: $\mu \geq 16$

Alternative hypothesis : $\mu$

The degrees of freedom on this case are:

$df=n-1=8-1=7$

Compute the test statistic

The statistic for this case is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{15.6-16}{\frac{0.3}{\sqrt{8}}}=-3.77$

Give the appropriate conclusion for the test

Since is a one side left tailed test the p value would be:

$p_v =P(t_{(7)}$

Conclusion

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

We can conclude that the mean is significantly less than 16 ounces at 10% of significance. so then the consumer suspect is correct.

3 0

3 years ago

Bài 4: Một vật dao động điều hòa với phương trình x = 4cos(4πt - π/3) cm.

ra1l [238]

Answer:

g

Explanation:

6 0

3 years ago