The flattened, rotating disk of gas and dust around the protosun, from which planets were believed to have formed, is called the

A boy with a mouse is 80 kg stands on a scale in an ascending elevator with an acceleration of 3 m/s What is the resultant upwar

Rus_ich [418]

Answer:

Upward force on the boy will be 1024 N

Explanation:

We have given mass of the boy m = 80 kg

Acceleration due to gravity $g=9.8m/sec^2$

It is given that elevator is ascending with acceleration of $3m/sec^2$

So net acceleration on the boy = 9.8+3 = 12.8 $m/sec^2$ ( As the car elevator is moving ascending )

So upward force on the boy will be equal to F = m(g+a)

So $F=80\times 12.8=1024N$

So upward force on the boy will be 1024 N

3 0

3 years ago

Please help me anything will help

spin [16.1K]

Your answer is C) The speed of sound is higher in solids than in liquids.

6 0

3 years ago

Alan and Monica tested how fertilizer X affected the growth of a plant. Alan and Monica put 100 grams of fertilizer X in pot 1.

BARSIC [14]

Answer:

D.

a control group

Explanation:

In a scientific experiment such as the one above, there is an experimental group and a control group. The experimental group is the group that receives the treatment while the control group does not receive any treatment. The control group helps the researcher to observe if the treatment had any significant effect.

In this case, it will help Alan and Monica to determine if fertilizer X actually had an effect on the plant. Therefore, the pot with o grams of fertilizer in it is the control group.

7 0

3 years ago

Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward the right with a spe

Blizzard [7]

Answer:

The right answer is D) the total momentum of the system is 0.047 kg · m/s toward the right.

Explanation:

Hi there!

The total momentum of the system is given by the sum of the momentum vectors of each cart. The momentum is calculated as follows:

p = m · v

Where:

p = momentum.

m = mass.

v = velocity.

Then, the momentum of the system will be the momentum of cart A plus the momentum of cart B (let´s consider the right as the positive direction):

mA · vA + mB · Vb

0.450 kg · 0.850 m/s + 0.300 kg · (- 1.12 m/s) = 0.047 kg · m/s

The right answer is D) the total momentum of the system is 0.047 kg · m/s toward the right.

6 0

3 years ago

A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with

beks73 [17]

Answer:

4.6 kHz

Explanation:

The formula for the Doppler effect allows us to find the frequency of the reflected wave:

$f'=(\frac{v}{v-v_s})f$

where

f is the original frequency of the sound

v is the speed of sound

vs is the speed of the wave source

In this problem, we have

f = 41.2 kHz

v = 330 m/s

vs = 33.0 m/s

Therefore, if we substitute in the equation we find the frequency of the reflected wave:

$f'=(\frac{330 m/s}{330 m/s-33.0 m/s})(41.2 kHz)=45.8 kHz$

And the frequency of the beats is equal to the difference between the frequency of the reflected wave and the original frequency:

$f_B = |f'-f|=|45.8 kHz-41.2 kHz|=4.6 kHz$

6 0

3 years ago

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