We know the answer doesn't have to do with force because we have not identified a positive or negative axis.
Depending on what the system we are evaluating is, the sign of the work can change.
If work is done on the system, it is negative, but if work is done by the system, it is positive.
If the system we are evaluating is the leash, the work is being done by the leash, and therefore, the work is positive.
If the system we are evaluating is the dog, the work is being done on the dog, and therefore, the work is negative.
<u>Answer:</u>
Positive acceleration is in third hour and negative acceleration is in second hour.
<u>Explanation:</u>
Velocity of car in first hour = 70 mph
Velocity of car in second hour = 60 mph
Velocity of car in third hour = 80 mph
Acceleration = Change in velocity / Time
Acceleration in second hour = (60 - 70)/1 = -10 mph²
Acceleration in third hour = (80 - 60)/1 = 20 mph²
So positive acceleration is in third hour and negative acceleration is in second hour.
Answer:
True
Explanation:
Objects falling through the air experience a force of opposition called air resistance
Answer:
76.74 Hz
Explanation:
Given:
Wave velocity ( v ) = 330 m / sec
wavelength ( λ ) = 4.3 m
We have to calculate Frequency ( f ):
We know:
v = λ / t [ f = 1 / t ]
v = λ f
= > f = v / λ
Putting values here we get:
= > f = 330 / 4.3 Hz
= > f = 3300 / 43 Hz
= > f = 76.74 Hz
Hence, frequency of sound is 76.74 Hz.
