#69) mary weighs soon. she walks down a flight or stairs to a level 5.50m
below her starting point, what is
the change in Mary's potential
thergy?

answer: 0

explanation: im   14

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.

the given statement is true.

sensory memory lasts for a fraction of seconds before the information is lost. it is the shortest -term memory and can be called as an element of memory. example: when we look at something and remember what it looks like, is just a second of observation. it degrades very quickly. it can also be considered as the process of perception rather than considering it as a memory.