Question

A force of 10 N acts for 20 second on a body of mass 2 kg initially at rest. Calculate the energy required
by the body and the work done by the applied force.

Answer 1

Answer:

U=0m/s

F=ma

a=F÷m

So,a=10÷1=10

S=ut+1/2 at×t

=1/2 ×10×16

=80

W=FS

10×80

=800J

Answer 2

Answer:

F = 10N

mass = 2kg

F = ma

a = F / m = 20 / 2 = 5m/s²

acceleration (a) = 5m/s²

time (t) = 20s

initial velocity (u) = 0

displacement (s) = ut + at²/2

s = 0 + 5×20² / 2

s= 5 × 20 × 20/2

s = 5 × 20 × 10  

s = 1000m

Work done = F × s

                   = 10×1000

                   = 10000j

v = u + at

v = 0 + 5×20

v = 100m/s

Kinetic energy = 1/2mv²

                        = 1/2 × 2 × 100 × 100

                        = 10000joules