' W ' is the symbol for 'Watt' ... the unit of power equal to 1 joule/second.
That's all the physics we need to know to answer this question.
The rest is just arithmetic.
(60 joules/sec) · (30 days) · (8 hours/day) · (3600 sec/hour)
= (60 · 30 · 8 · 3600) (joule · day · hour · sec) / (sec · day · hour)
= 51,840,000 joules
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Wait a minute ! Hold up ! Hee haw ! Whoa !
Excuse me. That will never do.
I see they want the answer in units of kilowatt-hours (kWh).
In that case, it's
(60 watts) · (30 days) · (8 hours/day) · (1 kW/1,000 watts)
= (60 · 30 · 8 · 1 / 1,000) (watt · day · hour · kW / day · watt)
= 14.4 kW·hour
Rounded to the nearest whole number:
14 kWh
1.3 A
If a clock expends 2 W of power from a 1.5 V battery, what amount of current is supplying
the clock?
solution
as we know
p=vi
i=p/v
=2/1.5
=1.3A
A. The amount of work increases.
Imagine you are pushing a box on a flat surface. Now imagine pushing it up a steep hill. It gets harder and that's how I remember this.
Hope this helps.
Given that,
Mass of each washer = 4.9 g
We need to calculate the mass of two washers in kg
Using conversion of unit
Mass of each washer 
So, Mass of two washers is
Put the value of m
If 4 washer are attached to the spring
We need to calculate the applied force on the car
Using formula of force
Put the value into the formula
Hence, (i), The mass of two washers is 0.0098 kg.
(ii). The applied force on the car is 0.192 N.
Frame of reference, in simplest terms, describes the state of motion of the observer. The frame of reference may also be described by using a set of coordinates, time and motion. We formulate all our equations and solve them using the frame of reference.
