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A body of mass 20kg climbs up 20 steps of the stairs in 20 seconds. If each step is 20cm high. What is the power used in climbing the stairs (g=10m/s2)
- a)400w
- b)20w
- c)40w
- d)200w
Correct answer is option 'C'. Can you explain this answer?
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Verified Answer
A body of mass 20kg climbs up 20 steps of the stairs in 20 seconds. If...
Mass = 20 kg, height = 20×20/100 m = 4m, time taken = 20 s. power = work done/ time, power = mgh/t. = 20×10×4/20 watt = 40 w.
Most Upvoted Answer
A body of mass 20kg climbs up 20 steps of the stairs in 20 seconds. If...
Given:
Mass of body (m) = 20 kg
Height of each step (h) = 20 cm = 0.2 m
Number of steps climbed (n) = 20
Time taken (t) = 20 s
Acceleration due to gravity (g) = 10 m/s^2
To find: Power used in climbing the stairs
Formula used:
Power (P) = Work done (W) / Time taken (t)
Work done (W) = Force (F) x Distance (d)
Calculation:
Distance covered by climbing one step = Height of one step = h = 0.2 m
Total distance covered by climbing all the steps = n x h = 20 x 0.2 = 4 m
Work done in lifting the body to climb all the steps = mgh
where g is acceleration due to gravity, h is the height climbed
Work done = 20 x 10 x 4 = 800 J
Power = Work done / Time taken
Power = 800 J / 20 s
Power = 40 W
Therefore, the power used in climbing the stairs is 40 W, option (c) is correct.
Mass of body (m) = 20 kg
Height of each step (h) = 20 cm = 0.2 m
Number of steps climbed (n) = 20
Time taken (t) = 20 s
Acceleration due to gravity (g) = 10 m/s^2
To find: Power used in climbing the stairs
Formula used:
Power (P) = Work done (W) / Time taken (t)
Work done (W) = Force (F) x Distance (d)
Calculation:
Distance covered by climbing one step = Height of one step = h = 0.2 m
Total distance covered by climbing all the steps = n x h = 20 x 0.2 = 4 m
Work done in lifting the body to climb all the steps = mgh
where g is acceleration due to gravity, h is the height climbed
Work done = 20 x 10 x 4 = 800 J
Power = Work done / Time taken
Power = 800 J / 20 s
Power = 40 W
Therefore, the power used in climbing the stairs is 40 W, option (c) is correct.
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Community Answer
A body of mass 20kg climbs up 20 steps of the stairs in 20 seconds. If...
Let the number of stairs be x
mass of body= 20kg
height of the stairs =20cm /100
=0.2m
number of stairs x=20
acceleration due to gravity= 10m/s²
(by manipulating the above information, we can easily identify the easiest way of obtaining the power using the general formula of POWER= WORKDONE/TIME TAKEN)
also work done =force x perpendicular distance
workdone = f. d
but since we were not given the value of force, we can derive it using the formula for finding force
Force = mass x acceleration
Force = 20kg x 10ms²
=200N
also distance covered by the body is got by multiplying the total number of stairs and the height in metres
Distance = h x X
= 0.2 x 20
. =4m
by replacing
W.D= 200N x 4m
= 800J
by further replacing for Power
Power = 800J/20 seconds
= 4440w
therefore the power used in climbing the stairs is 40watts....
mass of body= 20kg
height of the stairs =20cm /100
=0.2m
number of stairs x=20
acceleration due to gravity= 10m/s²
(by manipulating the above information, we can easily identify the easiest way of obtaining the power using the general formula of POWER= WORKDONE/TIME TAKEN)
also work done =force x perpendicular distance
workdone = f. d
but since we were not given the value of force, we can derive it using the formula for finding force
Force = mass x acceleration
Force = 20kg x 10ms²
=200N
also distance covered by the body is got by multiplying the total number of stairs and the height in metres
Distance = h x X
= 0.2 x 20
. =4m
by replacing
W.D= 200N x 4m
= 800J
by further replacing for Power
Power = 800J/20 seconds
= 4440w
therefore the power used in climbing the stairs is 40watts....
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A body of mass 20kg climbs up 20 steps of the stairs in 20 seconds. If each step is 20cm high. What is the power used in climbing the stairs (g=10m/s2)a)400wb)20wc)40wd)200wCorrect answer is option 'C'. Can you explain this answer?
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