Answer:
The answer is t = 23.81 s
Explanation:
A car in this question means those partition that make up the train
Let denote the the of each car as Z
The equation of motion that has to do with distance is given as
S = ut + (1/2)at²
Where u = initial velocity = 0
t = time = 9 s
Substituting these values we have
Z = (1/2) a(9)²
= 40.5 a
making acceleration the subject we have that a = Z / 40.5
Let us denote the length of the 7th car as =7Z
Considering the distance at the 7th car we have
S₇ = ut₇ + (1/2)at²₇
Where u = initial velocity =0
Substituting values we have
7Z = (1/2)(Z/40.5)(t₇)²
7 = {1/2 ×40.5}(t₇)²
t₇² = 7 × 2 × 40.5
t₇² = 567
t₇ = 23.81 s
Answer:
A perfectly elastic collision conserves momentum and kinetic energy..
5j-5i is her resultant displacement.
velocity in east= 5i
velocity in west=5j
resultant magnitude=√5i+√5j
displacement =5j-5i
Displacement is the shortest distance, but distance is the length of everything covered. A vector quantity with a magnitude and a direction is displacement. The vector (or straight line) separation between an initial and final position is described by this term. Therefore, all that is needed to determine the resulting displacement is to know these two positions.
Calculate the inverse tangent of the ratio of the components of the displacement in the y- and x-directions to find the direction of the displacement vector.
To know more about displacement visit : brainly.com/question/11934397
#SPJ9
Force = Mass x Acceleration
This is Newton's Second Law of Motion
Anyway,
450 = M x 15
450/15 = M
30kg = M
