Question

If you lift a bag of flour from the floor to a shelf 1.75 meters high in 3 seconds using 50 W of power, how much force are you applying to the bag?
85.7 N

262.5 N

29.2 N

57.1 N
@loser66

Answer 1

@.Sam.

Answer 2

@osprey

Answer 3

without wading through the arithmetic on this one (later, perhaps if asked again) I'd go for the lowest number of Newtons. Reason is that 29 N is quite a big force, and I'm thinking of lifting and doing yourself an injury by doing so. Which makes this a GUESSTIMATE.

Answer 4

i need to be sure on this question could you please help me work it out through numbers @osprey

Answer 5

@Elsa213

Answer 6

@mathmate

Answer 7

Try not to use the answer options.
Do your own calculations and then find a match.
hint:
Power=F*D/t
so
F=Power*t/D (in suitable units)

Answer 8

29.16

Answer 9

That's the most realistic one if the calc is right, which I hope it is.
@mathmate medal for the 'rith ... hope we're right ...

Answer 10

it was 85.7

Answer 11

@18jonea

F=power*time/height
=50 watts*3 seconds / 1.75 m
note 1 watt = 1 N-m/s
=50 N-m/s * 3 s / 1.75 m
= 50*3/1.75 \(\frac{N-m \times s}{s \times m}\)
= 85.7 N

so the last answer is correct.