Due in 40 explain in terms of frame of reference if you’re inside a moving train everything on the outside can seem to be moving

A frame of reference can be thought of as the state of motion of the observer of some event. For example, if you're sitting on a lawn chair watching a train travel past you ... you could even watch a glass of water sitting on a table inside the train move ... This seems like a simple and obvious example, yet when you take a step

sonar - device which is used to find the submit submarines, sankalp ship. sonar waves consists of a transmitter and detector which are installed in the observation centre on board of a ship. the ultrasonic waves are sent into the sea at high frequency about 1000 khz in all direction.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.