A ball of mass 0.1kg is thrown vertically upwards with a speed of 10ms-1 from the top of a tower 10m high. Neglecting air resistance, its total energy just before hitting the ground is
(take g = 10ms-2)
A
5 J
B
10 J
C
15 J
D
20 J
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Total Energy = Kinetic Energy + Potential Energy
P.E = mgh = 0.1 x 10 x 10= 10 J
K.E = \(\frac{1}{2}\) MV\(^2\) = \(\frac{1}{2}\) x 0.1 x 10\(^2\) = 0.5 x 0.1 x 100 = 5J
T.E = K.E + P.E = 5 + 10 = 15J
Source: Myschool Past Questions Archive (Record #313)