Answer: 1224 joules
Explanation:
Given variables are:
Power (p) = 68 W
Time taken (t) = 18 seconds
work done (w) = ?
Recall that power is the rate of work done per unit time i.e Power is obtained by dividing the work done by the time taken.
Hence, Power = work / time
Make work the subject formula
work = power x time
work = 68 watts x 18 seconds
work = 1224 joules
Thus, 1224 joules of work is done.
The cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.
<h3>
Cost of electricity for 3 kW kettle</h3>
The cost is calculated as follows;
1 unit = 9p /kWh
Total energy consumed by 3 kW kettle, E = P x t
where;
- P is power (kW)
- t is time in (hr)
E = 3 kW x (3 mins/60 mins/hr)
E = 0.15 kWh
Energy cost = 9 p/kWh x 0.15 kWh = 1.35 P
Thus, the cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.
Learn more about energy cost here: brainly.com/question/13795167
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Answer:
Time taken by the arrow to travel along to hit the ground is 0.55 seconds.
Explanation:
The only "force" acting on the "crossbow" to cause it to "hit" the ground is "gravity". There is no initial velocity downward when it shoot.
d = the displacement of the object
t = the time for which the object moved
a = acceleration of the object
= the initial velocity of the object
Given values
d = 1.5 m
t = unknown
Square root both sides
t = 0.55 s
Answer:
y = 4 Sin (2πt)
Explanation:
Amplitude, A = 4
frequency, f = 1
Wave function is given by
y = A sinωt
where, ω is angular frequency
ω = 2 π f = 2 π x 1 = 2π
So, the desired wave function
y = 4 Sin (2πt)