Which of the following is true about a hypothesis?

17. A volleyball weighs about 300 grams.

atroni [7]

Answer:

PE = 44.1 J

Explanation:

Ok, to have the specific data, the first thing we must do is convert from grams to kilograms. Since mass must always be in kilograms (kg)

We have:

1 kilograms = 1000 grams.

We convert it using a rule of 3, replacing, simplifying units and solving:

$\boxed{\bold{x=\frac{gr*1\ kg}{1000\ gr}=\frac{300\ gr*1\ kg}{1000\ gr}=\frac{300\ kg}{1000}=\boxed{\bold{0.3\ kg}}}}$

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Earth's gravity is known to be 9.8 m/s², so we have:

Data:

m = 0.3 kg
g = 9.8 m/s²
h = 15 m
PE = ?

Use formula of potencial energy:

$\boxed{\bold{PE=m*g*h}}$

Replace and solve:

$\boxed{\bold{PE=0.3\ kg*9.8\frac{m}{s^{2}}*15\ m}}$

$\boxed{\boxed{\bold{PE=44.1\ J}}}$

Since the decimal number, that is, the number after the comma is less than 5, it cannot be rounded, then we have this result.

The potential energy of the volleyball is 44.1 Joules.

Greetings.

8 0

3 years ago

A mechanical device requires 500j of work to do 200j of work in lifting a box. What is the efficiency of the device?

olga55 [171]

40% the formula is work output/work input*100 so
200/500=.4*100=40

5 0

2 years ago

A 0.70-kg basketball dropped on a hardwood floor rises back up to 65% of its original height. (a) If the basketball is dropped f

dem82 [27]

Answer:

Part a)

$Loss = 3.6 J$

Part b)

$Loss = 0.99 J$

Part C)

This is loss in terms of thermal energy due to collision with the floor

Explanation:

Part a)

Since we know that the ball rises up by 65% of initial height

so after first bounce it will lose 35% of its initial energy

so we will have

$U = mgH$

Energy Loss = 0.35 mgH[/tex]

$Loss = 0.35(0.70)(9.81)(1.5)$

$Loss = 3.6 J$

Part b)

Energy of the ball after first bounce

$U_1 = 0.65 mgH$

energy of ball after 2nd Bounce

$U_2 = 0.65(0.65 mgH)$

energy of the ball after 3rd bounce

$U_3 = (0.65)(0.65^2)mgH$

$U_3 = 0.65^3(0.70)(9.81)(1.5)$

$U_3 = 2.83 J$

Now we will have energy loss in fourth bounce given as

$Loss = 0.35 U_3$

$Loss = 0.35(2.83)$

$Loss = 0.99 J$

Part C)

This is loss in terms of thermal energy due to collision with the floor

7 0

3 years ago

4. In a object filled with a type of gas, which of the following actions would decrease the pressure

ExtremeBDS [4]

Answer:

Decrease the number of gas particles, increase the object's area, and reduce the temperature of the gas

Explanation:

TEMPERATURE:

Decreasing the temperature will slow down the molecules. Hence, less no. of collisions will take place between walls of object and molecules. This will result in decrease of pressure.

Therefore, the pressure of a gas can be decreased by increasing its temperature.

NUMBER OF GAS PARTICLES:

Decreasing the number of particles will result in less no. of collisions, hence decreasing the pressure.

Therefore, the pressure of a gas can be decreased by decreasing its no. of molecules or no. of particles.

AREA OF OBJECT:

The pressure is given by the formula:

$P = \frac{F}{A}\\\\For constant Force (F):\\P\ \alpha\ \frac{1}{A}$

where,

A = Area of Object

Therefore, the pressure of a gas can be decreased by increasing area of object.

So, the correct option is:

Decrease the number of gas particles, increase the object's area, and reduce the temperature of the gas

7 0

2 years ago

Air has pressure because

IrinaVladis [17]

B
Correct me if i am wrong

4 0

2 years ago