Question

Questions on work (I am lost in this so any help would be appreciated):

1. A frictionless 1kg cart is initially at rest. If you push the cart
1m on level ground with a constant horizontal force of 1N,
what is its final speed?
2. What is the work needed to lift a 1kg box 1m in the air?
3. If you use a two pulley system to lift a 1kg box, so that the
tension need to lift the box is only half of the box's weight,
what is the work needed to lift a 1kg box 1m in the air?
4. What is the power needed to drive a 1000kg car up a 30°
incline at a constant speed of 10m/s? Ignore air resistance

Answer 1

5. An 8nm thick cell membrane maintains an electric potential of 100mV between the
cytoplasm (top) and cell exterior (bottom). This acts like a battery to power ATP
synthase. If it takes 1/10th of an electron-Volt (0.1eV = 1.6x10-20J, energy) for the
electric gradient to pull a proton through the membrane, what is the average electric
force on a proton as it is pulled through the membrane? (Is ΔElectric PE + or – ?)

A) 0 N B) 2x10-12 N C) 5x1010 N D) not enough information

Answer 2

at 1, u have to mention the time

Answer 3

@Arnab09 it wasn't given

Answer 4

Actually I think 1 is sqrt2 m/s and 2 is 9.8 J so i could cross those off my list

Answer 5

hey u der i can help u
for 1 qn we have u=0 v=? a=1 f=1 m=1 s=1
now we can fint v by newtons third law
v^2=u^2 + 2as

Answer 6

v^2=2
v=sqrt2

Answer 7

v^2=2
v=sqrt2
v=1.414 m/sec

Answer 8

F=mg and theta will be 90 degree
u knw work =FScostheta
work=10x1 x0
work=0

Answer 9

this is the figure of 3 qn