Answer:

Explanation:
Each time the work done to raise a given mass is

here we know that


now we have


since it is just 25% of actual energy consumed as we know its efficiency is 25%
so we have total energy consumed in this way


now if it took N number of times so burn the fat of a pizza then


Answer:
120 volts is the root mean square (rms) average of the voltage as it varies with time.
Explanation:
A. The average voltage over many weeks of time (false)
Reason: Average AC voltage over one cycle is cycle (from one peak to other) is zero and so over many weeks of time it is zero.
B. The peak voltage from an AC wall receptacle (false)
Reason: The peak voltage of an AC source in North America is zero.
C. The arithmetic mean of the voltage as it varies with time (false)
Reason: Arithmetic mean AC voltage over one cycle is cycle (from one peak to other) is zero and so over many weeks of time it is zero.
D. One-half the peak voltage (false)
Peak voltage =170 Volts
One-half the peak voltage = 85 volts
E. The root mean square (rms) average of the voltage as it varies with time (True)
Reason:
The peak voltage and root mean square voltage are related by:

Average value of voltage over one cycle is zero, so instead of calculating average voltage for AC peak voltage is first squared and the mean is calculated.
Answer:
v = 72.54 m/s
Explanation:
We have,
Length of a guitar string is 0.62 m
Frequency of a guitar string is 234 Hz
For guitar string,

The velocity of the wave in the string is given by :

So, the velocity of the waves in the string is 72.54 m/s.
Newton's first law says that the tableware will remain motionless unless acted upon by an outside force.
Answer: How much gravitational potential energy does the ball have at this point? At h = 20.4 m the gravitational potential energy of the ball reaches maximum.
How much work did I do lifting up the ball? As you are lifting the object you are doing work on the object. The work W done on an object by a constant force is defined as W = F·d. It is equal to the magnitude of the force, multiplied by the distance the object moves in the direction of the force.