Physics MCQ help

[Waleed Mir]

Forces of 30N and 50N act on the same body but in different directions. Which value could not be the resultant force on the body?

A 10N B 30N C 50N D 70N

 

[usman ijaz]

A 10N is the ans....if u add the both forces u will get 80N the max force...and if u subtract u will get 20N.....leaving the 10N ans...

 

[hassan50306]

^agreed! Answer is A: 10 N
the answer has to be in the range of 20 to 50 newtons
or simplly: 20N ≤ recquired resultant force ≤ 80 N

 

[TaffsAsLevel]

Any one can help me with 71. answer is B

 

[areela hassan]

Any one can help me with 71. answer is B

well since they said that the force and distance become 2s and 2d first of all we will assume that distance is o.4 and force is 10(assuming here) so it will give us k.e of 4 and They say that it changes to 8 so 4j will increase no matter what
now u take 2s and 2d which will give you (20*2) and (0.4 * 2) and u wil get 16 now simply add 4j k.e which will increase and u will get 20 which is the answer

 

[TaffsAsLevel]

well since they said that the force and distance become 2s and 2d first of all we will assume that distance is o.4 and force is 10(assuming here) so it will give us k.e of 4 and They say that it changes to 8 so 4j will increase no matter what
now u take 2s and 2d which will give you (20*2) and (0.4 * 2) and u wil get 16 now simply add 4j k.e which will increase and u will get 20 which is the answer

How about June 2007 Number 40. paper 1. How is the answer C? Isn't it the heaviest nucleus that have the lowest speed?

 

[areela hassan]

plz

How about June 2007 Number 40. paper 1. How is the answer C? Isn't it the heaviest nucleus that have the lowest speed?

upload the question plz

 

[h4rriet]

How about June 2007 Number 40. paper 1. How is the answer C? Isn't it the heaviest nucleus that have the lowest speed?

There's also the acceleration to consider. a=F/m. F=Exq. Therefore a=Eq/m. E is the same for all; q and m differ. So a=q/m. 3/7 is smaller than 1/1, 2/4 & 4/9.

 

[TaffsAsLevel]

There's also the acceleration to consider. a=F/m. F=Exq. Therefore a=Eq/m. E is the same for all; q and m differ. So a=q/m. 3/7 is smaller than 1/1, 2/4 & 4/9.

What I did was equate qV to EK, why won't it be similar? Thanks though for replying

 

[h4rriet]

What I did was equate qV to EK, why won't it be similar? Thanks though for replying

Because velocity is changing. There's acceleration, you see.