A train travelling at 18m/s accelerates uniformly at 2m/s² for 6 seconds. Calculate the final speed of the train.

Find the magnitude of acceleration (ft/s^2) a person experiences when he or she is texting and driving 58mph, hits a wall, and c

SVEN [57.7K]

Answer:

350 ft/s²

Explanation:

First, convert mph to ft/s.

58 mi/hr × (5280 ft/mi) × (1 hr / 3600 s) = 85.1 ft/s

Given:

v₀ = 85.1 ft/s

v = 0 ft/s

t = 0.24 s

Find: a

v = at + v₀

a = (v − v₀) / t

a = (0 ft/s − 85.1 ft/s) / 0.24 s

a = -354 ft/s²

Rounded to two significant figures, the magnitude of the acceleration is 350 ft/s².

7 0

4 years ago

You are investigating the report of a UFO landing in an isolated portion of New Mexico, and encounter a strange object that is r

SIZIF [17.4K]

Answer: 5 m

Explanation:

We have the following data:

$I_{1}=0.11 W/m^{2}$ is the intensity of the sound at 7.5 m from the source

$r_{1}=7.5 m$ is the distance at which the intensity $I_{1}$ was measured

$I_{2}=1 W/m^{2}$ is the intensity of the sound at $r_{2}$ from the source

We have to find $r_{2}$

Since the object is radiating the signal uniformly in all directions, we can use the <u>Inverse Square Law for Intensity:</u>

$\frac{I_{1}}{I_{2}}=\frac{r_{2}^{2}}{r_{1}^{2}}$

Isolating $r_{2}$ :

$r_{2}=r_{1}\sqrt{\frac{I_{1}}{I_{2}}}$

$r_{2}=7.5 m\sqrt{\frac{0.11 W/m^{2}}{1 W/m^{2}}}$

$r_{2}=2.48 m$ This is the distance at which the intensity is the "threshold of pain"

Now, we have to substract this value to $r_{1}$ to find how much closer to the source can we move:

$r_{1}-r_{2}=7.5 m - 2.48 m=5.02 m \approx 5 m$

3 0

3 years ago

Read 2 more answers

If the graph shown is a position-time graph of an object moving at constant velocity, what is the velocity of the object? Assume

belka [17]

Answer:

C.) v = 50 m/s

Explanation:

The relationship between position vs. time graph and velocity is that the derivative (slope) of the position vs. time graph gives you velocity. In other words, find the slope to get the velocity.

Select two arbitrary points. I'll choose (3s, 225m) and (0s, 75m).

Now use the slope equation:

$v = \frac{y_{2} - y_{1} }{x_{2} - x_{1}} =\frac{225 - 75}{3-0} = 50 m/s$

v = 50 m/s

Hopes this helps!

5 0

3 years ago

A ball is thrown straight off a 150 meter high roof at 20 m/s.

juin [17]

Answer:

I'll try and find the answer for you:)

Explanation:

I can't promise you I will though

7 0

3 years ago

A high-speed train travels 480 km from Paris to Grenoble, France, at an average speed of 180 km/h. How long will it take to reac

KengaRu [80]

The number of hours it will take for the high-speed train to reach Grenoble is the ratio between the distance to the speed. For this item, the equation would be,
t = d / s
Substituting,
t = 480 km / 180 km/h = 2.7 h
Thus, it will take approximately 2.7 hours to reach Grenoble.

7 0

3 years ago