REALLY NEED HELP WITH THIS!!!

Julie drives 100 mi to Grandmother's house. On the way to Grandmother's, Julie drives half the distance at 30.0 mph and half the

salantis [7]

Answer:

Explanation:

Given

Distance to grandmother's house=100 mi

it is given that during return trip Julie spend equal time driving with speed 30 mph and 70 mph

Let Julie travel x mi with 30 mph and 100-x with 70 mph

$\frac{x}{30}=\frac{100-x}{70}$

x=30 mi

Therefore

Julie's Average speed on the way to Grandmother's house $=\frac{100}{\frac{50}{30}+\frac{50}{70}}$

=42 mph

On return trip

$=\frac{100}{2\frac{30}{30}}=50 mph$

6 0

3 years ago

Radon-220 is a radioactive gas. It escapes from underground rocks and causes a large part of the natural background radiation in

Sergeu [11.5K]

Answer: 134 neutrons are there in the nucleus of Radon-220

Explanation:

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

Thus, number of protons = atomic number = 86

Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.

Mass number = Number of protons + Number of neutrons

220 = 86 + Number of neutrons

Number of neutrons = 134

5 0

3 years ago

A bumper cart has a mass of 200 kg and has a protective bumper around it that behaves like a spring. The spring constant is 5000

34kurt

Part A:
For this part we’re assuming all the kinetic energy of the moving bumper car is converted into elastic potential energy in the spring since the car is brought to rest. Therefore you can find the total kinetic energy to get your answer:

KE = ½ mv^2
KE = ½ (200)(8)^2
KE = 6400 J

Part B:
Now you can use Hooke’s law to find the force:

F = kx
F = (5000)(0.2)
F = 1000 N

4 0

3 years ago

Alternating Current In Europe, the voltage of the alternating current coming through an electrical outlet can be modeled by the

stealth61 [152]

Answer:

$\frac{50}{\pi }$ Hz

Explanation:

In alternating current (AC) circuits, voltage (V) oscillates in a sine wave pattern and has a general equation as a function of time (t) as follows;

V(t) = V sin (ωt + Ф) -----------------(i)

Where;

V = amplitude value of the voltage

ω = angular frequency = 2 π f [f = cyclic frequency or simply, frequency]

Ф = phase difference between voltage and current.

Now,

From the question,

V(t) = 230 sin (100t) ---------------(ii)

By comparing equations (i) and (ii) the following holds;

V = 230

ω = 100

Ф = 0

But;

ω = 2 π f = 100

2 π f = 100 [divide both sides by 2]

π f = 50

f = $\frac{50}{\pi }$ Hz

Therefore, the frequency of the voltage is $\frac{50}{\pi }$ Hz

7 0

2 years ago

A grandfather clock has a pendulum that consists of a thin brass disk of radius r = 13.62 cm and mass 1.199 kg that is attached

Feliz [49]

Answer:

Explanation:

Expression for time period of a pendulum is as follows

T = $2\pi\sqrt{\frac{l}{g} }$

l is length of pendulum from centre of bob and g is acceleration due to gravity

Given

Time period T = 1.583

g = 9.846

Substituting the values

1.583 = $2\pi\sqrt{\frac{l}{9.846} }$

l = $\frac{(1.583)^2\times9.846}{4\times(\frac{22}{7})^2 }$

l = .6244 m

= 62.44 cm

Length of rod = length of pendulum - radius of bob

= 62.44 - 13.62

= 48.82 cm

= .488 m

8 0

2 years ago