起重机将质量为750kg的货物在0.5min内匀速吊起6m高,则:1)起重机做了多少功?2)起重机的功率是多少?(g=10N/kg)
问题描述:
起重机将质量为750kg的货物在0.5min内匀速吊起6m高,则:1)起重机做了多少功?2)起重机的功率是多少?
(g=10N/kg)
答
G=mg=750kg×10N/kg=7500N
W=Gh=7500N×6m=45000J
P=W/t=45000J/30s=1500W
答
(1)
做功
=mgh
=750×10×6
=45000J
(2)
功率
=45000÷(0.5×60)
=1500W