' 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
__________________________________
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
Answer:
a)
b)
c)
d)
e)
Explanation:
Given that:
- initial speed of turntable,

- full speed of rotation,

- time taken to reach full speed from rest,

- final speed after the change,

- no. of revolutions made to reach the new final speed,

(a)
∵ 1 rev = 2π radians
∴ angular speed ω:

where N = angular speed in rpm.
putting the respective values from case 1 we've


(c)
using the equation of motion:

here α is the angular acceleration



(b)
using the equation of motion:





(d)
using equation of motion:



(e)
using the equation of motion:



Answer:
B. 4 m/s
Explanation:
v=d/t
Running for 300 m at 3 m/s takes 100 seconds and running at 300 m at 6 m/s takes 50 seconds. 100 s + 50 s = 150 s (total time). Total distance is 600 m, so 600 m/ 150 s = 4 m/s.
Answer:
65.3
Explanation:
W = (1/2)mv^2
W = (1/2)(0.145kg)(30m/s)^2