Question

An athlete with mass 70 kg trains by performing press-ups with a load on his back. The diagram shows the perpendicular distances involved.
The centre of mass of the athlete is CM and the centre of mass of the load he is carrying is CL.

The mass of the load is 6.0 kg.
What is the upward force exerted by his two arms?

A 54N B 76N C 540N D 760N

give proper full explanation. brainliest, 5 star rating then only. good luck solving it.

Answer 1

Answer:

Weight = mass x gravitational field

           = 6kg x 10N/kg

           = 60N

Weight = mass x gravitational field

           = 70kg x 10N/kg

           = 700N

the pivot will be at the man's foot

Anti-clockwise moment = Clockwise moment.

So, we can substitute, when we find the value of one of the moment - either clockwise or anti-clockwise.

man

Anti-clockwise moment = force x distance

                                       = 700N x 0.9

                                       = 630Nm

load

Anti-clockwise moment= 60x(0.9+0.3)

                                     = 60 x 1.2m

                                     =70Nm

total moment is 702Nm (630+70)

As a result, we now know the moment of the clockwise moment, enabling us to find the upward force.

Moment= force x distance

             = ?N    x 1.3m

702Nm  = ?N x 1.3

divide by 1.3 both side

540N =?N

Force is 540N

Hope this helps!