Chapter 10, Problem 82A

a.

To determine

To Explain: The person who does more work.

Answer to Problem 82A

Both person do same work.

Explanation of Solution

Given:

Masses of both persons climbing stairs is same i.e. $m$

Distance climbed by both persons is same i.e. $d$

Time taken by first person to climb the stairs is $t_1=25\text{s}$

Time taken by first person to climb the stairs is $t_2=35\text{s}$

As work done is given by,

  $W=F_{g}d=mgd$

Since, mass and distance climbed is same.

So, work done by both person will be same.

b.

To determine

Which person produce more power.

Answer to Problem 82A

The first person produces more power.

Explanation of Solution

Given:

Masses of both persons climbing stairs is same i.e. $m$

Distance climbed by both persons is same i.e. $d$

Time taken by first person to climb the stairs is $t_1=25\text{s}$

Time taken by first person to climb the stairs is $t_2=35\text{s}$

As power is given by,

  $P=\frac{W}{t}$

Since, work done by both is same.

So, power developed is inversely proportional to time.

As first person takes less time to climb same height, he will produce more power.