How many 2.5 kg bricks can man carry up a staircase 3.6 m high in one hour if he works at an average rate of 9.8 watt?

Question

How many 2.5 kg bricks can man carry up a staircase 3.6 m high in one hour if he works at an average rate of 9.8 watt? (A) 800 (B) 200 (C) 600 (D) 400

Tardigrade Admin · Accepted Answer

Work done by man in one hour = power × time =9.8 × 1 × 60 × 60 J Work done by man in raising one brick =m g h =2.5 × 9.8 × 3.6 J Number of bricks N=(9.8 × 1 × 60 × 60/2.5 × 9.8 × 3.6)=400

Q. How many $2.5 k g$ bricks can man carry up a staircase $3.6 m$ high in one hour if he works at an average rate of $9.8$ watt?

800

200

600

400

Work done by man in one hour = power $\times$ time
$= 9.8 \times 1 \times 60 \times 60 J$
Work done by man in raising one brick $= m g h$
$= 2.5 \times 9.8 \times 3.6 J$
Number of bricks $N = \frac{9.8 \times 1 \times 60 \times 60}{2.5 \times 9.8 \times 3.6} = 400$

Q. How many 2.5kg bricks can man carry up a staircase 3.6m high in one hour if he works at an average rate of 9.8 watt?

800

200

600

400

Work done by man in one hour = power × time =9.8×1×60×60J Work done by man in raising one brick =mgh =2.5×9.8×3.6J Number of bricks N=2.5×9.8×3.69.8×1×60×60​=400

Q. How many $2.5 k g$ bricks can man carry up a staircase $3.6 m$ high in one hour if he works at an average rate of $9.8$ watt?

Work done by man in one hour = power $\times$ time
$= 9.8 \times 1 \times 60 \times 60 J$
Work done by man in raising one brick $= m g h$
$= 2.5 \times 9.8 \times 3.6 J$
Number of bricks $N = \frac{9.8 \times 1 \times 60 \times 60}{2.5 \times 9.8 \times 3.6} = 400$