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olga_2 [115]
3 years ago
11

A 615 N student standing on a scale in an elevator notices that the scale reads 645 N. From this information, the student knows

that the elevator must be moving Group of answer choices You cannot tell if it is moving upward or downward. upward. downward.
Physics
1 answer:
BARSIC [14]3 years ago
8 0

Answer:

The elevator must be moving upward.

Explanation:

During the motion of an elevator, the weight of the person deviates from his or her actual weight. This temporary weight during the motion is referred to as "Apparent Weight". So, when the elevator is moving downward, the apparent weight of the person becomes less than his or her actual weight.

On the other hand, for the upward motion of the elevator, the apparent weight of the person becomes more than the actual weight of that person.

Since the apparent weight (645 N) of the student, in this case, is greater than the actual weight (615 N) of the student.

<u>Therefore, the elevator must be moving upward.</u>

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Which method of popcorn popping transfers heat into the kernels without any direct
Ivanshal [37]

Answer:

you plug in and turn on the popper, and then the hot air begins to rise in the popper while cooler air falls. As hot air circulates past the popcorn kernels and so the kernels absorb the hear

8 0
3 years ago
If a cup of coffee has temperature 95∘C95∘C in a room where the temperature is 20∘C,20∘C, then, according to Newton's Law of Coo
lina2011 [118]

Answer:

T = 76.39°C

Explanation:

given,

coffee cup temperature = 95°C

Room temperature= 20°C

expression

T( t ) = 20 + 75 e^{\dfrac{-t}{50}}

temperature at t = 0

T( 0 ) = 20 + 75 e^{\dfrac{-0}{50}}

T(0) = 95°C

temperature after half hour of cooling

T( t ) = 20 + 75 e^{\dfrac{-t}{50}}

t = 30 minutes

T( 30 ) = 20 + 75 e^{\dfrac{-30}{50}}

T( 30 ) = 20 + 75 \times 0.5488

T(30) = 61.16° C

average of first half hour will be equal to

T = \dfrac{1}{30-0}\int_0^30(20 + 75 e^{\dfrac{-t}{50}})\ dt

T = \dfrac{1}{30}[(20t - \dfrac{75 e^{\dfrac{-t}{50}}}{\dfrac{1}{50}})]_0^30

T = \dfrac{1}{30}[(20t - 3750e^{\dfrac{-t}{50}}]_0^30

T = \dfrac{1}{30}[(20\times 30 - 3750 e^{\dfrac{-30}{50}} + 3750]

T = \dfrac{1}{30}[600 - 2058.04 + 3750]

T = 76.39°C

4 0
3 years ago
In a typically constructed research study, the experimental group is selected:
blondinia [14]

Answer:

D. from a separate pool than is the control group.

Explanation:

in the picture the person answers is backwards but...

hope this helps have a nice day

7 0
2 years ago
Find the ratio of the lengths of the two mathematical pendulums, if the ratio of periods is 1.5​
juin [17]

Answer:

The ratio of lengths of the two mathematical pendulums is 9:4.

Explanation:

It is given that,

The ratio of periods of two pendulums is 1.5

Let the lengths be L₁ and L₂.

The time period of a simple pendulum is given by :

T=2\pi \sqrt{\dfrac{l}{g}}

or

T^2=4\pi^2\dfrac{l}{g}\\\\l=\dfrac{T^2g}{4\pi^2}

Where

l is length of the pendulum

l\propto T^2

or

\dfrac{l_1}{l_2}=(\dfrac{T_1}{T_2})^2 ....(1)

ATQ,

\dfrac{T_1}{T_2}=1.5

Put in equation (1)

\dfrac{l_1}{l_2}=(1.5)^2\\\\=\dfrac{9}{4}

So, the ratio of lengths of the two mathematical pendulums is 9:4.

3 0
3 years ago
While sitting in a swivel chair, you push against the floor with your heel to make the chair spin. The 6.7 N frictional force is
nexus9112 [7]

Answer:

I = 1.4kgm²

Explanation:

The rotational motion is caused by the frictional force, which generates a torque on the system. As there is no other force that creates a torque, this can be expressed in the equation of rotational motion below:

\tau_f =I\alpha\\\\

And \tau_f=rf, where r is the distance from the point of application and the rotation axis, and f is the magnitude of the frictional force. This is because the frictional force is applied in the direction that causes the greatest angular acceleration (this is, 90°) and rf\sin90\°=rf. Then, we have that:

rf=I\alpha\\\\\implies I=\frac{rf}{\alpha}\\\\

Plugging in the given values, we obtain:

I=\frac{(0.39m)(6.7N)}{1.8rad/s^{2} } =1.4kgm^{2}

In words, the total moment of inertia is equal to 1.4kgm².

6 0
3 years ago
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