In a longitudinal wave the particle displacement is parallel to the direction of wave propagation. ... The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions.Answer:
Explanation:
Kinetic friction (also referred to as dynamic friction) is the force that resists the relative movement of the surfaces once they're in motion.
https://www.khanacademy.org › stat...
Static and kinetic friction example (video) | Khan Academy
Answer a would be static friction
Answer b is fluid friction
(Air resistance is fluid friction. Fluid friction is the friction experienced by objects which are moving in a fluid and the air is a fluid.)
Answer c is static friction
ANSWER D IS KINETIC FRICTION
Hope this helps :D
Adding thermal energy
Performing work on the system
for acceleration we can define that rate of change in velocity is know as acceleration
So whenever velocity of train is changing with time we can say train is accelerating
Now here if initially train is standstill then after some time its speed is 5 m/s
so here the train is accelerated first time
Then on straight path its speed changed from 5 m/s to 10 m/s so here train gets accelerated second time
After this train chugged around a curve with same speed 10 m/s
SO here since train is moving in curve so here its direction of velocity is continuously changing and this type of acceleration is known as centripetal acceleration
SO this is accelerated Third time
Then its speed decreases and it comes to speed of 5 m/s from 10 m/s
So here it is acceleration of train for Fourth time
Then finally train comes to stop so again its speed changed from 5 m/s to 0
so this is acceleration of train Fifth time
So total train will accelerate 5 times in whole path
