Answer:
velocity = 0.3m/s
speed = 1.21 m/s
Explanation:
The total time it takes to get from the front door to the bench is
t = 27 + 39 = 66 seconds
The net displacement from the front door to the bench is the distance from the front door to the windmill subtracted by the distance from the windmill to the bench
s = 50 - 30 = 20 m
So the average velocity is net displacement divided by total time
v = s / t = 20 / 66 = 0.3 m/s
The total distance from the front door to the bench is the sum of distance from the front door to the windmill and the distance from the windmill to the bench
S = 50 + 30 = 80 m
So the average speed is total distance divided by total time
v = s / t = 80 / 66 = 1.21 m/s
Answer:
The minimum force that must be exerted by the mechanic at the end of a 30 cm-long wrench to loosen the nut is 110N
Explanation:
Torque = Fd sin θ
For a torque, the minimum force must be applied perpendicular to the lever arm, so that θ = 90° and sin θ = sin 90° = 1
Torque = 33 N.m
F = Force applied = ?
d = 30 cm = 0.3 m
F = Torque/d = 33/0.3 = 110 N
Answer:
Explanation:
When two coherent light beams travel different paths and arrive at a point , there will be difference in the length of path travelled by them . If this difference is zero then both will reinforce each other and their brightness will add up . Hence there will be constructive interference .
If their path difference is not zero but it is equal to odd multiple of their half wavelength like λ / 2 , 3 λ / 2 , 5 λ /2 , 7 λ /2 etc , then instead of reinforcing each other , they will destroy each other . This is called destructive interference . As a result of it , darkness will prevail at the point where they meet or interfere.
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.
