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3 years ago

Also need help with 20 & 21 please

Physics

2 answers:

SSSSS [86.1K]3 years ago

5 0

Number 20 is B and 21 is C

Hoochie [10]3 years ago

5 0

A density is a physical change

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You're driving your new sports car at 80 mph over the top of a hill that has a radius of curvature of 540 m. What fraction of yo

luda_lava [24]

Answer:

75.84%

Explanation:

We were given Speed of the sports car, v as 80 mph , we can convert to m/s for unit consistency.

v=80mph= 35.76 m/s

The radius of curvature is given as , r = 540 m

✓ the normal weight can be denoted as Wn

✓ the apparent weight of the person can be denoted as Wa

Wn= normal weight= mg

Wa=apparent weight = (mg - mv^2/r)

g= acceleration due to gravity= 9.8m/s^2

The apparent weightand normal weight has a ratio of

Mn/Ma= [mg - mv^2/r]/mg ........eqn(1)

If we simplify eqn(1) we have

Mn/Ma=[g - vr^2/g].............eqn(2)

Then substitute the given values

Mn/Ma=9.8 - [(35.76^2)/540]/ 9.8

=0.758×100%

Mn/Ma=75.84%

Hence, the required fraction is 75.84%

4 0

3 years ago

A healthy environment depends on biogeochemical cycles maintaining a balance of input and output. When forests are cut down, whi

Ann [662]

The correct answer will be c

8 0

3 years ago

Read 2 more answers

If the system is operated on mars, through what distance would the 18.0-kg mass have to fall to give the same amount of kinetic

-Dominant- [34]

The previous part of the exercise says:
"<span>Engineers are designing a system by which a falling mass m imparts kinetic energy to a rotating uniform drum to which it is attached by thin, very light wire wrapped around the rim of the drum. There is no appreciable friction in the axle of the drum, and everything starts from rest. This system is being tested on Earth, but it is to be used on Mars, where the acceleration due to gravity is 3.71 m/s². In the Earth tests, when m is set to 18.0 kg and allowed to fall through 5.50 m, it gives 300.0 J of kinetic energy to the drum."

Since Kearth = Kmars, we have, for conservation of energy, that also the potential energies must be equal:
Uearth = Umars

which means:
m </span>· gearth · hearth = m · gmars <span>· hmars

we can solve for hmars:
hmars = (gearth / gmars) </span>· hearth
= (9.8 / 3.71) · 5.50
= 14.53m

Therefore, the correct answer will be: the mass would have to fall from an height of 14.53m.

5 0

3 years ago

A potter’s wheel moves from rest to an angular speed of 0.40 rev/s in 37.5 s.

svlad2 [7]

The angular acceleration of the potter's wheel is 0.067 rad/s².

The given parameters:

Final angular speed, ωf = 0.4 rev/s
Time of motion, t = 37.5 s

<h3>What is angular acceleration?</h3>

Angular acceleration of an object is the rate of change of angular speed of the object.

The angular acceleration of the potter's wheel is calculated as follows;

$\alpha = \frac{\Delta \omega }{t} \\\\\alpha = (0.4\ rev/s \times \frac{2 \pi \ rad}{1 \ rev} ) \times \frac{1}{37.5 \ s} \\\\\alpha = 0.067 \ rad/s^2$

Thus, the angular acceleration of the potter's wheel is 0.067 rad/s².

Learn more about angular acceleration here: brainly.com/question/25129606

5 0

2 years ago

What happens to the position of an object as an unbalanced force acts on it? Give an example.

Evgesh-ka [11]

Hi! I'm a few days late since I just saw this question just now, but I'll answer anyway.

Answer:

When an unbalanced force acts on a moving object, the velocity of the object will change. Change in velocity means a change in speed, direction, or both. For example, if you kick a soccer ball and it moves from one place to another, it means that unbalanced forces are acting upon it. The ball moves from one place to another after kicking it so the position changed.

8 0

3 years ago