wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A boy of mass 40 kg runs up a flight of 50 steps, each 10 cm high in 14 s. So, work done by the boy is:

A
1960 J
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
19.6 J
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
980 J
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
9.8 J
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A 1960 J
Mass of the boy, m=40 kg
Number of steps = 50
Height of each step = 10 cm
Force on the boy due to gravity, F=mg=40×9.8N=392 N
While climbing up the steps, the boy does work against gravity.
Displacement in the vertical direction, s=(50×10) cm=500 cm=5 m
Displacement is in the direction of force applied by the boy against gravity.
So, work done, W=F×s=392×5 J=1960 J

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Potential Energy
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon