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3 years ago

5

A weightlifter lifts a weight of 500 N from the ground over her head, a distance of 1.8 m. How much work has been done to move t

he weight?

1 answer:

Maksim231197 [3]3 years ago

3 0

Answer is 900N

Hope this helps c:

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Change in Energy Quick Check

nika2105 [10]

Answer:

The force of gravity on the object decreases. (FALSE)

The potential energy of the object decreases. (TRUE)

The acceleration due to gravity decreases. (FALSE)

The kinetic energy of the object decrease (FALSE)

Explanation:

<u>FORCE OF GRAVITY:</u>

Force of gravity on the object is the weight of object, which depends upon the mass and value of acceleration due to gravity (W = mg). Since, the value mass is constant on Earth and acceleration due to gravity is also constant on earth.

Therefore, force of gravity remains same on the object. <u>The statement is false.</u>

<u></u>

<u>POTENTIAL ENERGY:</u>

Potential energy of object depends upon the mass, value of acceleration due to gravity, and change in height of object (P.E = mgΔh). Since, the value mass is constant on Earth and acceleration due to gravity increases as the object moves towards the surface of earth. But, the height of object is decreasing.

Therefore, potential energy of object decreases. <u>The statement is true.</u>

<u></u>

<u>ACCELERATION DUE TO GRAVITY:</u>

Acceleration due to gravity depends upon the altitude (gh = g[1 - 2h/Re]). Since, the height of object is decreasing.

Therefore, acceleration due to gravity increases. <u>The statement is false.</u>

But, this change is not significant.

<u>KINETIC ENERGY:</u>

Kinetic Energy of object, which depends upon the mass and velocity of the object (K.E = mv²/2). Since, the value mass is constant on Earth and velocity increases as the object moves towards the surface of earth.

Therefore, kinetic energy of the object also increases. <u>The statement is false.</u>

4 0

3 years ago

If you double the pressure on the surface of a can of water, the buoyant force on a stone placed in that water will

Bingel [31]

The buoyant force won't change.

4 0

3 years ago

Caroline conducts research on how the amount of fiber in a student's breakfast affects their grades in school. How should she re

Evgesh-ka [11]

Answer:

data table and line graph ( first choice)

8 0

3 years ago

Read 2 more answers

Which tem decorbes the perceived frequency of a sound wave?

JulsSmile [24]

Pitch

Explanation:

The pitch of a sound wave is the perceived frequency of a sound wave.

The quality of sound that makes it discernible to the ear is the pitch.

Sound wave is a longitudinal wave that is transmitted by series of rarefaction and compression.
Pitch helps to distinguish between the different sound qualities.
Pitch is how high or low sound is perceived.

learn more:

Pitch brainly.com/question/9772227

Sound wave brainly.com/question/2845448

#learnwithBrainly

5 0

3 years ago

Read 2 more answers

A 300 g glass thermometer initially at 23 ◦C is put into 236 cm3 of hot water at 87 ◦C. Find the final temperature of the thermo

DIA [1.3K]

Answer:

$74^{\circ} C$

Explanation:

We are given that

Mass of glass, $m=300 g$

$T_1=23^{\circ}$

Volume, $V=236cm^3$

Mass of water= $density\times volume=1\times 236=236 g$

Density of water= $1g/cm^3$

Temperature of hot water, $T=87^{\circ}$

Specific heat of glass, $C_g=0.2cal/g^{\circ}C$

Specific heat of water, $C_w=1 cal/g^{\circ}C$

$Q_{glass}=m_gC_g(T_f-T_1)=300\times 0.2(T_f-23)$

$Q_{water}=m_wC_w(T_f-T)=236\times 1(T_f-87)$

$Q_{glass}+Q_{water}=0$

$300\times 0.2(T_f-23)+236\times 1(T_f-87)$

$60T_f-1380+236T_f-20532=0$

$296T_f=20532+1380=21912$

$T_f=\frac{21912}{296}=74^{\circ} C$

5 0

3 years ago