Answer:
C. 900J (i tried my best)
Step-by-step explanation:
the student's mass=60kg
gravitational field strength= 10N/kg:
1kg = 10N
60kg = 600N
(where 600N is the gravitational field strength of the student)
√1.5²+2² (pythagoras theorem)
=2.5m (the stairs' length)
work done= N x distance move in the direction of force (m)
=600N x 2.5m
=1500J @ Nm
1500J - 600N (gravitational field strength of the student)
=900J(??)
-correct me if i'm wrong i'm just a human :)