A ball of mass 8 kg falls from rest from a height of 100 m. Neglecting air resistance, calculate its total energy after falling a distance of 40 m.
Correction:
P.E. = Mgh = 8*9.8*100 = 7840 J. = Potential energy = Total energy.
P.E. = Mgh = 8*9.8*(100-40) = 4704 J. = Total energy after falling 40 m.
K.E. = 7840 - 4704 = 3136 J.
F=mg
F=8×10
=80N
W=Fd
In this case our distance is the height which is 100. But we are looking for the workdone after 40m so it'll be
W=80×40
W=3200J.
The end!
(M=8kg, h=100m, g=10m/s
P.E= MGH=8×100×10=8000J or 8KJ)for the height of 100m.
(M=8kg, h=40m, g=10m/s
P.E= MGH=8×40×10=3200J or 3.2KJ)for the height of 40m.
pe=mgh=8×10×100=8000j at 100m .then at 40m will be=8×10×40=3200 therefore ke+pe implies mgh ke alone will be 8000_ 3200=4800 am i right?
I don't understand
P.E =mgh
8kg×10ms-2×(100×40)m
8×10×4000=320,000joules