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3 years ago

A car traveling at a speed of 30 m/s encounters an emergency and comes to a complete

Physics

1 answer:

Natasha2012 [34]3 years ago

4 0

Answer:

Explanation:

Use the one-dimensional equation

$v_f=v_0+at$ which says that the final velocity of an object is equal to the object's initial velocity plus its acceleration times time. We are looking for time. That means the equation looks like this:

0 = 30 + (-4)t and

-30 = -4t so

t = 7.5 sec

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Having landed on a newly discovered planet, an astronaut sets up a simple pendulum of length 1.38 m and finds that it makes 441

Tasya [4]

The period of a simple pendulum is given by:
$T=2 \pi \sqrt{ \frac{L}{g} }$
where L is the pendulum length, and g is the gravitational acceleration of the planet. Re-arranging the formula, we get:
$g= \frac{4 \pi^2}{T^2}L$ (1)

We already know the length of the pendulum, L=1.38 m, however we need to find its period of oscillation.

We know it makes N=441 oscillations in t=1090 s, therefore its frequency is
$f= \frac{N}{t}= \frac{441}{1090 s}=0.40 Hz$
And its period is the reciprocal of its frequency:
$T= \frac{1}{f}= \frac{1}{0.40 Hz}=2.47 s$

So now we can use eq.(1) to find the gravitational acceleration of the planet:
$g= \frac{4 \pi^2}{T^2}L = \frac{4 \pi^2}{(2.47 s)^2} (1.38 m) =8.92 m/s^2$

3 0

3 years ago

The inductance of a closely packed coil of 560 turns is 8.9 mH. Calculate the magnetic flux through the coil when the current is

Y_Kistochka [10]

Answer:

$0.11\times 10^{-6}weber$

Explanation:

We have given number of turns N = 560

Inductance L = 8.9 mH

Current through the coil = 7 mA

Inductance of the coil is given as $L=\frac{N\Phi }{I}$

Where N is number of turns I is current and $\Phi$ is flux

So $\Phi =\frac{LI}{N}=\frac{8.9\times 10^{-3}\times 7\times 10^{-3}}{560}=0.11\times 10^{-6}weber$

6 0

3 years ago

Read 2 more answers

if a bowling ball hits a wall a force of 6 N, the wall exerts a force of how much back. on the bowling ball

grigory [225]

It would exert the same back right?

3 0

2 years ago

An intravenous (IV) system is supplying saline solution to a patient at the rate of 0.06 cm3/s through a needle of radius 0.2 mm

horsena [70]

Answer:

Pressure applied to the needle is 7528 Pa

Explanation:

As we know by poiseuille's law of flow of liquid through a cylindrical pipe

the rate of flow through the pipe is given as

$Q = \frac{\Delta P \pi r^4}{8\eta L}$

now we know that

$Q = 0.06 \times 10^{-6} m^3/s$

radius = 0.2 mm

Length = 6.32 cm

$\eta = 1\times 10^{-3} Pa s$

now we have

$6 \times 10^{-8} = \frac{\Delta P \pi (0.2 \times 10^{-3})^4}{8(1 \times 10^{-3})6.32 \times 10^{-2}}$

$3.03 \times 10^{-11} = \Delta P 5.02 \times 10^{-15}$

$\Delta P = 6028 Pa$

now we have

$P - 1500 = 6028 Pa$

$P = 7528 Pa$

8 0

2 years ago

What is the instantaneous speed of the monkey at time t=5s?

bezimeni [28]

I’m assuming we’re suppose to get some kind of graph but, Instantaneous speed is the speed that is happening right now. Like driving a car at 15k/h. The instantaneous speed of the car 15k/h. On the graph, at 5s. Wherever the line is, will tell you what the speed is.

6 0

3 years ago