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Vika [28.1K]
3 years ago
13

rollercoaster car starts at a height of 90 m at Point A and is moving at a speed of 20 m/s on a later hill at point C. Assuming

friction does not affect the motion of a car, what is its height at point C.
Physics
1 answer:
Temka [501]3 years ago
5 0

OH Cool! So.. 9.8 * 90 = 1/2 * 20 ^2 + 9.8 * hc
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A Ferris wheel on a California pier is 27 m high and rotates once every 32 seconds in the counterclockwise direction. When the w
Leto [7]

A) 140 degrees

First of all, we need to find the angular velocity of the Ferris wheel. We know that its period is

T = 32 s

So the angular velocity is

\omega=\frac{2\pi}{T}=\frac{2\pi}{32 s}=0.20 rad/s

Assuming the wheel is moving at constant angular velocity, we can now calculate the angular displacement with respect to the initial position:

\theta= \omega t

and substituting t = 75 seconds, we find

\theta= (0.20 rad/s)(75 s)=15 rad

In degrees, it is

15 rad: x = 2\pi rad : 360^{\circ}\\
x=\frac{(15 rad)(360^{\circ})}{2\pi}=860^{\circ} = 140^{\circ}

So, the new position is 140 degrees from the initial position at the top.

B) 2.7 m/s

The tangential speed, v, of a point at the egde of the wheel is given by

v=\omega r

where we have

\omega=0.20 rad/s

r = d/2 = (27 m)/2=13.5 m is the radius of the wheel

Substituting into the equation, we find

v=(0.20 rad/s)(13.5 m)=2.7 m/s

6 0
3 years ago
What kind of charge does an object have when it has given away electrons?
Step2247 [10]
Electrons have a negative charge, so if you give away electrons, you give away negative charge, thus ending with a positive charge.
6 0
3 years ago
Read 2 more answers
A tree is standing in the middle of a meadow. As you watch, the wind begins
Klio2033 [76]

Answer:

B) The tree was stationary and began to move.

Explanation:

This situation can be explained by using Newton's first law of motion, which states that

"An object at rest (or in motion at constant velocity) stays at rest (or in motion at constant velocity) unless a net non-zero force is exerted on it"

This means that an object at rest can start moving if and only if there is a net non-zero force acting on it.

In the example in the problem, the tree is initially stationary. Later, it started to move. According to Newton's first law, therefore, there must be a net force that caused this change of state of motion of the tree. Therefore, the correct answer is

B) The tree was stationary and began to move.

8 0
3 years ago
g A spherical container of inner diameter 0.9 meters contains nuclear waste that generates heat at the rate of 872 W/m3. Estimat
zhannawk [14.2K]

Answer: The total rate of heat transfer from the container to its surroundings ignoring radiation is 332.67 W.

Explanation:

Given: Inner diameter = 0.9 m

q = 872 W/m^{3}

Now, radii is calculated as follows.

r = \frac{diameter}{2}\\= \frac{0.9}{2}\\= 0.45 m

Hence, the rate of heat transfer is as follows.

Q = q \times V

where,

V = volume of sphere = \frac{4}{3} \pi r^{3}

Substitute the values into above formula as follows.

Q = q \times \frac{4}{3} \pi r^{3}\\= 872 W/m^{3} \times \frac{4}{3} \times 3.14 \times (0.45 m)^{3}\\= 332.67 W

Thus, we can conclude that the total rate of heat transfer from the container to its surroundings ignoring radiation is 332.67 W.

3 0
3 years ago
A stretched string has a mass per unit length of 5.12 g/cm and a tension of 19.3 N. A sinusoidal wave on this string has an ampl
Sati [7]

Answer:

a. 0.143 mm b. 77.6 rad/m c. 483.18 rad/s  d. +1

Explanation:

a. ym

Since the amplitude is 0.143 mm, ym = amplitude = 0.143 mm

b. k

We know k = wave number = 2π/λ where λ = wavelength.

Also, λ = v/f where v = speed of wave in string = √(T/μ) where T = tension in string = 19.3 N and μ = mass per unit length = 5.12 g/cm = 5.12 ÷ 1000 kg/(1 ÷ 100 m) = 0.512 kg/m and f = frequency = 76.9 Hz.

So, λ = v/f = √(T/μ)/f

substituting the values of the variables into the equation, we have

λ = √(T/μ)/f

= √(19.6 N/0.512 kg/m)/76.9 Hz

= √(38.28 Nkg/m)/76.9 Hz

= 6.187 m/s ÷ 76.9 Hz

= 0.081 m

= 81 mm

So, k = 2π/λ

= 2π/0.081 m

= 77.6 rad/m

c. ω

ω = angular frequency = 2πf where f = frequency of wave = 76.9 Hz

So, ω = 2πf

= 2π × 76.9 Hz

= 483.18 rad/s

d. The correct choice of sign in front of ω?

Since the wave is travelling in the negative x - direction, the sign in front of ω is positive. That is +1.

4 0
3 years ago
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