Question

a body of mass 5kg initially at rest is subjected to a force of 20 N.what is the kinetic energy acquired by the body at the end of 10 sec?

Answer 1

ANSWER-4000 J
HOW TO -
CONSTANT Accelaration -a=f/this is Newton second law of motion  solved for acceleration. (4 m/s^2)
Final velocity: Vf = Vi + a•t (40 m/s)
Kinetic Energy is KE= ½⋅m⋅v² (4,000 J)

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Answer 2

m=5kg
t. =10s
F=20N
we know that force is mass multiplied by acceleration
F=ma
using above values
a=F/m
a=20/5
$a = 4 \frac{m}{ {s}^{2} }$
$v = \frac{a}{t}$
$v = 0.4 \frac{m}{s}$
now. kinetic energy of a body is given by,
$ke = \frac{1}{2} m {v}^{2}$
using the values,
ke = 5×0.4×0.4/2=4J
therefore ke=4J