Question 26
A man is running in a
straight line.
What is an approximate
value of his kinetic energy?
A 10 J B 100 J C 1000 J D 10 000 J
Reference: Past Exam Paper – March 2016 Paper 12 Q16
Solution:
Answer: C.
Kinetic energy = ½ mv2
At A-level, we should be
able to estimate some quantities.
Assume the mass of the man
to be 60 kg.
An Olympic athlete may be
assumed to run at 10 m s-1.
A normal person’s speed
would be less, say 6 m s-1.
KE = ½ mv2 = ½ × 60 × 62 = 1080 J
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