Frequency is no. of times this wave vibrates or complete its one cycle per unit time. As it vibrates 30000 times per second its frequency is 30000 per second or 30000 Hz [1 Hz = once per second].
Answer:
98%
Explanation:
Given parameters
Mass of motor = 10kg
Height = 2m
Time = 2s
Power input = 100w
Unknown
Efficiency = ?
Solution
Efficiency is the percentage of the power output to the power input.
Power is the rate at which work is done.
Power output = mass x g x height / time
g is the acceleration due to gravity
Power output = 10x 2 x 9.8 / 2 = 98W
Efficiency = power output/ power input x 100
Efficiency = 98/100 x 100 = 98%
The answer is A.
Explanation:
We know that the average acceleration a for an interval of time Δt is expressed as:
a = Δv
Δt
where Δv is the change in velocity that occurs during Δt.
e formula for the instantaneous acceleration a is almost the same, except that we need to indicate that we're interested in knowing what the ratio of Δv to Δt approaches as Δt approaches zero.
We can indicate that by using the limit notation.
So, the formula for the instantaneous acceleration is:
a = lim Δv
Δt→0 Δt
The question in choice-C is the correct answer to your question.
(Is this confusing ?)
