You and a friend each carry a 15 kg suitcase up two flights of stairs, walking at a constant speed. Take each suitcase to be the
system. Suppose you carry your suitcase up the stairs in 30 s while your friend takes the 60s.
Which of the following is true?
a. You did more work, but both of you expended the same power.
b. You did more work and expended more power.
c. Both of you did the same work, but you expended more power.
d. Both of you did the same work, but you expended less power.
Which of the following is true?
a. You did more work, but both of you expended the same power.
b. You did more work and expended more power.
c. Both of you did the same work, but you expended more power.
d. Both of you did the same work, but you expended less power.
1 answer:
Answer:
Both of you did the same work but you expended more power.
Explanation:
<em>Work done</em> by an object is calculated by force applied multiplied by the distance.
W=F*d
From the figure given below let us calculate force applied bith you and yopur friend.
Let us take the stairs in positive x direction,
Work done by you W₁ ,
The force applied Fₓ = F - mgsinθ =maₓ
here aₓ = 0, because both of you move with constant speed
F - mgsinθ = 0
F= mgsinθ
The work done by you on the suitcase is
W = F L cos0° , where L is he length of the staircase.
W = FL = mgsinθL , by substituting value of F
Work done by you is W₁ = mgLsinθ
Similarly work done by your friend is W₂ = mgLsinθ.
Because both of you carry suitcase of same weight and in staircase is in same angle the force applied is same .
Therefore <em>work done by both of you is same</em> . Both of you did equal work.
The power , is defined as amount of energy converted or transfered per second or rate at which work is done .
P = =
Power spend by you P₁ = mgLsinθ/t
P₁ = 15*9.8*Lsinθ/30
P₁ = 4.9L sinθ eqn 1
Power spend by your friend is P₂ = mgLsinθ/t
P₂ =15*9.8*Lsinθ/60
P₂ = 2.45Lsinθ eqn 2
Dividing eqn 1 and eqn 2
P₁ = 2P₂
You have spend more power than your friend .
Hence Both of you did equal work but you spend more power.
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Answer:
The power output of this engine is
The the maximum (Carnot) efficiency is
The actual efficiency of this engine is
Explanation:
From the question we are told that
The temperature of the hot reservoir is
The temperature of the cold reservoir is
The energy absorbed from the hot reservoir is
The energy exhausts into cold reservoir is
The power output is mathematically represented as
Where t is the time taken which we will assume to be 1 hour = 3600 s
W is the workdone which is mathematically represented as
substituting values
So
The Carnot efficiency is mathematically represented as
The actual efficiency is mathematically represented as
substituting values
Answer:
<em>The new force is 2/3 of the original force</em>
Explanation:
<u>Coulomb's Law </u>
The electrical force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between the two objects.
Written as a formula:
Where:
q1, q2 = the objects' charge
d= The distance between the objects
Suppose the first charge is doubled (2q1) and the second charge is one-third of the original charge (q2/3). Now the force is:
Factoring out 2/3:
Substituting the original force:
The new force is 2/3 of the original force