Question

Dallas says that any change in velocity is directly proportional tothe time interval over which the change took place. Dana says thatis true only when the acceleration is constant. Which one, ifeither, is correct?
a. Dana,because it is true then the acceleration is constant
b. Dallas,because we can define ax, avg so thatDvx= ax, avgt.
c. Dallas,because ax, avg always is equalto
d. Allthe above are correct.
e. Only(a) and (b) above are correct

Answer 1

Answer:

e. Only(a) and (b) above are correct

Explanation:

Impulse

= Fx t = m ( v-u )

v-u = change in velocity

F x t = mass x change in velocity

change in velocity = F t / mass

=a t

change in velocity ∝ t ( time ) , if a is constant

dv = a_avg  dt

∫dv = a_avg ∫dt

v-u = a_avg t

change in velocity ∝ t ( time )

So both (a) and (b) are correct.