Question

a block of 20 kg mass is pulled up a slope by applying a force acting parallel to the slope if the slope makes an angle of 30 degree with the horizontal calculate the work done in pulling the load up to a distance of 3 M (use equals to 10 M per second square). (neglect work done against friction)

Answer 1

1.mass = 20kg

weight=force=20*10=200N

s=3m

w.d=fs

=200*3

=600J

potential energy=600J

2.u=18kmph=5m/s

v=9kmph=2.5m/s

w.d=change in K.E=1/2m(v2 -u2)

=1/2*70*(2.52-52)

=35*7.5*-2.5

=-656.25J

change in k.e=656.25J(as w.d is a scalar quantity)

initial k.E=1/2*70*5*5

=875J

final K.E=initial K.E-change in K.E

=875-656.25

=218.75J

no k.E o not reduce by half.It reduced by one fourth.

Answer 2

Answer:

see the attachment

Explanation:

W is work

M is mass

A is angle

S is displacement

and g is acceleration due to gravity