Question

Two children ,say A and B , each weighing 20 kg,climb a rope up to the height of 10m. The child A takes 10s,and B 20s to climb .
a). Find Find work A and B both
b). Out of these 2 children , who has more power ?compare !
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Answer 1

Answer:

(A)  The work done by both boy is 2000 joule

B) power of child A is 200 j/s and power of child B is 100 j/s , So, child A has more power han child B .

Explanation:

Given as :

The weight of each child = m = 20 kg

The height of rope = h = 10 meters

Time taken by child A to climb rope = 10 sec

Time taken by child B to climb rope = 20 sec

According to question

(a)

For child A

Work done = mass × g × height              ,,,,,,where g = 10 m/s

So, work done = 20 kg × 10 m/s × 10 m

∴   Work done = 2000 j

For child B

Work done = mass × g × height              ,,,,,,where g = 10 m/s

So, work done = 20 kg × 10 m/s × 10 m

∴   Work done = 2000 j

Hence, The work done by both boy is 2000 joule . Answer

(b) For child A

∵ Power is define as rate of doing work

power = $\dfrac{work}{time}$

Or, power = $\dfrac{2000}{10}$

∴    power = 200 j/s

For child B

power = $\dfrac{work}{time}$

Or, power = $\dfrac{2000}{20}$

∴   power = 100 j/s

Hence, power of child A is 200 j/s and power of child B is 100 j/s , So, child A has more power han child B .Answer

Answer 2

Answer:

(A)  The work done by both boy is 2000 joule

B) power of child A is 200 j/s and power of child B is 100 j/s , So, child A has more power han child B .

Explanation:

Given as :

The weight of each child = m = 20 kg

The height of rope = h = 10 meters

Time taken by child A to climb rope = 10 sec

Time taken by child B to climb rope = 20 sec

According to question

(a)

For child A

Work done = mass × g × height              ,,,,,,where g = 10 m/s

So, work done = 20 kg × 10 m/s × 10 m

∴   Work done = 2000 j

For child B

Work done = mass × g × height              ,,,,,,where g = 10 m/s

So, work done = 20 kg × 10 m/s × 10 m

∴   Work done = 2000 j

Hence, The work done by both boy is 2000 joule . Answer

(b) For child A

∵ Power is define as rate of doing work

power =  $\frac{work}{time}$

Or, power =  $\frac{work}{time}$

∴    power = 200 j/s

For child B

power =  

Or, power =  

∴   power = 100 j/s

Hence, power of child A is 200 j/s and power of child B is 100 j/s , So, child A has more power than child B .