Weight of Astronaut during Lift Off: 750N at 5g's Acceleration

[electricsound]

1. What is the weight of an astronaut during lift off, if his actual weight is 750N and the acceleration of the craft is 5g's.
The way I tried to solve it:
F=ma
F= 75(50)
But answers are not matching, as the answer should be 4500N.
I think I am missing something with that has to do with the upward acceleration...

 

[tiny-tim]

Hi electricsound!

Hint: what would his weight be if the acceleration of the craft was zero?

 

[electricsound]

Hi electricsound!

Hint: what would his weight be if the acceleration of the craft was zero?

At zero acceleration it would be 750N,
I cannot understand how to work out problems when acceleration is involved, even after consulting some worked examples in the book. For example problems which involve elevators and finding the weight of an object while accelerating, finding acceleration of a train using a pendulum suspended from the roof of a carriage... Bdw this is not homework, sorry if I mis placed this post, this is the problem I encountered during revision

 

[tiny-tim]

At zero acceleration it would be 750N,

ok, at 0g it's 750N, so at 5g it's … ?

 

[electricsound]

I really have no idea how to work it out...

 

[tiny-tim]

The weight is the reaction force …

find how many forces are there on the astronaut, then use F_total = ma

 

[electricsound]

Thanks a lot mate I understood..
at a= 50ms^-2
W-750= 75(50)
W=3750+750
W=4500N

thanks again...