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love history [14]
3 years ago
13

A child in a boat throws a 4.5kg package out horizontally with a speed of 13 m/s. Calculate the velocity of the boat immediately

after, assuming it was initially at rest. The mass of the child is 24 kg and the mass of the boat is 53 kg.
Physics
1 answer:
Varvara68 [4.7K]3 years ago
4 0

Answer:

0.78m/s

Explanation:

Now the momentum ensued by the boy throwing the package Is

Mass of package × velocity of package =4.5×13=58.5m/s

This momentum initiated a momentum on the boy-boat system

Total mass of the boy-boat system is 24+53=75kg

Let the velocity ensued by the boat be v.

Hence from conservation of momentum

58.5 =75×v

v= 58.5/75= 0.78m/s

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Answer:

See below

Explanation:

Photosynthesis is the process in which green plants use sunlight to make their own food. Photosynthesis requires sunlight, chlorophyll, water, and carbon dioxide gas. It is the process in which the chlorophyll in the leaves of the plant use the sunlight and water to convert the carbon dioxide gas into energy for the plant to use.

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2 years ago
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I need help with part D
natka813 [3]
1).  The little projectile is affected by friction all the way through the block.
Friction robs some kinetic energy.

2).  The block is affected by friction as it scrapes along the top of the post.
Friction robs some kinetic energy.

3).  The block is also affected by friction with the air (air resistance) as it
falls to the ground.  Friction robs some kinetic energy.
8 0
3 years ago
Look at the circuit below. What is the voltage between points C and D?
stepan [7]

Option c) 1.5 V

Explanation:

<em>As the circuit is build in series first we will find the current passing through the complete circuit. Current stays the same in each element is the series cirucuit, however, the voltage is different.</em>

Voltage is given by the following formula:

V = IR

<em>Because we have to find current through whole circuit, we will first find resistance of the whole circuit.</em>

Equivalent Resistance R(eq): R1 + R2 = 60 + 60 = 120 ohm

Current passing through whole circuit be:

I = \frac{V}{R(eq)}\\I = \frac{3}{120} = 0.025


Now we will find out the voltage between C and D:

Current stays the same in series circuit: I = 0.025 c

Resistance between C and D is, R = 60 ohm

Voltage becomes, V = IR = 0.025 * 60 = 1.5 V





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3 years ago
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A yellow ball with a mass of 2 kg is rolling across the floor at 3 m's A red ball with a mass of 3 kg is rolling across the
Wewaii [24]
Answer:
The red ball has a greater kinetic energy, because it has a greater mass

Explanation:
Mass is directly proportional to kinetic energy, as one increases, so does the other
6 0
3 years ago
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Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kc
Sergeeva-Olga [200]

Answer:

a) The student must run flight of stairs to lose 1.00 kg of fat 709.5 times.

b) Average power

P(w)= 1062.07 [w]

P(hp)=1.42 [hp]

c) This activity is highly unpractical, because the high amount of repetitions he has to due in order to lose, just 1 Kg of fat.

Explanation:

First, lets consider the required amount of work to move the mass of the student. (considering running stairs just as a vertical movement)

Work:

W= F*d= m*g*d

Where m is the mass of the student, g is gravity (9.8 m/s) and d is the total distance going up the stairs (0.15m *85steps= 12.75m )

W= F*d= m*g*d=85* 9.8*12.75=10620.75 [J]

Converting from Joules to Kcals:

\frac{10620.75}{4186} =2.537 Kcal

Now lets take into account the efficiency of the human body (20%)

2.537 ---> 20%

 x       ---> 100%

x=\frac{2.537*100}{20} =12.685

So the student is consuming 12.685 KCals each time he runs up the stairs.

Now,

1 g --> 9 Kcals

1000 g --> 9000KCals

Burning 1 g of fat, requieres 9 KCals, 1000g burns 9000KCals. So in order to burn a 1Kg of fat:

\frac{9000Kcals}{12.685Kcals} =709.5 times

He must run up the stairs 709.5 times, to burn 1 Kg of fat.

********************

For b) just converting units, taking into account the time lapse. (53103.75 is the 100% of the energy in joules, from converting 12.685Kcals to joules)

Power=\frac{Joules}{Seconds} =\frac{53103.75}{50} =1062.075 [W]\\

P(hp)=\frac{P(w)}{745.7} =\frac{1062.075}{745.7} =1.42[hp]

*****

4 0
3 years ago
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