Answer:

Explanation:
Static friction occurs when an object initially starts at rest. When the surfaces of the materials touch, the microscopic unevenness interlock greatest with each other, causing the most friction out of the three.
During sliding friction, an object is already moving or in motion. The microscopic surfaces still interlock, but because the object is in motion, it has a momentum. Therefore, the magnitude of sliding friction is less than that of static friction.
Rolling friction occurs when an object rolls across some surface. Rather than surfaces interlocking, rolling friction is caused by the constant distortion of surfaces. As it rolls, the surfaces of the object are constantly wrapping and changing. This distortion causes the rolling friction. However, it is much less in magnitude when compared to static or sliding friction.
Answer: A
Explanation: We know that f=p*n
f=50*300=15000 Hz = 15kHz.
Have a great day! <3
Answer:
90 J
Explanation:
W=fd
W=(75)(1.2)
W= 90 J
Answer:
c. 2.6 h
Explanation:
The longest time spent over dinner is the time that you have available minus the minimum possible time spent in the trip.
The time of the trip is found using:
t = 
Where distance is d and velocity is v. The time will be minimum at maximum velocity. Replacing with the data we have:
Ttrip =
= 8.1818 h
Tdinner = 10.8h - 8.1818 h = 2.6181h
that aproximates 2.6 h.