An object of mass 0.25kg moves at a height h above the ground with a speed of 4ms-1, if its mechanical energy at this height is 12 J, determine the value of h. [g = 10ms-1]

Ohiekulous

3 years ago

data:
m = 0.25 kg
v = 4 m/s
h = ?
g = 10m/s²
M.E = 12 J
M.E = P.E + K.E
P.E = M.E - K.E
but K.E = ½ mv² = 0.5×0.25×4² = 2 J
P.E = 12 - 2 = 10 J
P.E = mgh
make h the subject, h = P.E/mg = 10/(0.25×10) = 4
h = 4 m

Night_Ghost

2 years ago

please the answer is wrong
you're assuming the potential energy to be max at that point
which isn't true
an object can not have both velocity and height simultaneously at it's max
so the object is somewhere in the middle of the motion
total energy anywhere not at the max points=p.e+k.e=0.25x10xh+0.5x0.254²
12=2.5hx2
2.5h=10
h=10/2.5=4m

leoflex

10 years ago

There is a spelling error

any word that starts with any of the English vowels must use the article an

REF: check the dictionary

melayozie

1 year ago

g=10m/s

Mhykeejnr

1 year ago

Answer=4.0m