Atoy friction car is propelled forward from rest by a girl's hand which causes it to reach a forward velocity of 3.5m/s in 0.4 seconds. it is then rreleased and later stops in 5.6 seconds

a)  Acceleration =

b) Slow down acceleration = 0.625

c) Car travels 9.8 m

Explanation:

  Acceleration = Change in velocity/Time

a) Change in velocity = 3.5-0 = 3.5 m/s

   Time = 0.4 seconds

    Acceleration =

b) Change in velocity = 0 - 3.5 = -3.5 m/s

   Time = 5.6 seconds

   Acceleration =

   Slow down acceleration = 0.625

c) We have equation of motion, , where u is the initial velocity, u is the final velocity, s is the displacement and a is the acceleration.

 Here v = 0 m/s, u = 3.5 m/s, a = -0.625

 Substituting

  So, car travels 9.8 m

Step-by-step explanation:

Let w represent the width of the floor. Then the length of the floor is (w+4) and its area is ...

  A = LW

  525 = (w+4)(w)

  w^2 +4w -525 = 0

  (w -21)(w +25) = 0 . . . . factor the above

Solutions are ...

  w = 21, w = -25

We are interested in the positive solution: w = 21.

The floor is 21 feet wide and 25 feet long.

Alternate solution

Sometimes, when the factors aren't obvious, it works well to write an equation for the average of the dimensions. Here, we can represent that with x, and use (x-2) for the width, and (x+2) for the length. Then we have ...

  525 = (x-2)(x+2) = x^2 -4

  529 = x^2

  √529 = 23 = x

Then w=23 -2 = 21, and the length is w+4 = 25.