问题
选择题
某同学学习了功率后想估测自己跑步上楼的功率,他从一楼跑到三楼用了10s,他上楼的功率是( )
A.3W
B.30W
C.300W
D.3000W
答案
质量约为50kg,一层楼高约为4m,一楼到三楼是两层楼高,楼高为8m.
上楼的功率:P=
=W t
=Gh t
=mgh t
=400W50kg×10N/kg×8m 10s
故选C.
某同学学习了功率后想估测自己跑步上楼的功率,他从一楼跑到三楼用了10s,他上楼的功率是( )
A.3W
B.30W
C.300W
D.3000W
质量约为50kg,一层楼高约为4m,一楼到三楼是两层楼高,楼高为8m.
上楼的功率:P=
=W t
=Gh t
=mgh t
=400W50kg×10N/kg×8m 10s
故选C.