Everything Science Grade 10

(Marvins-Underground-K-12) #1

CHAPTER 21. MOTION IN ONE DIMENSION 21.7


Step 5:Substitute the values and calculate the final velocity

~vf = ~vi+at
~vf = 0m·s−^1 + (8m·s−^2 )(4s)
= 32m·s−^1 East

Step 6:Time at half the distance: Find an equation to calculate the time
We can use Equation 21.3:

∆~x = ~vi+^12 ~at^2

32 m = (0m·s−^1 )t+^12 (8m·s−^2 )(t)^2
32 m = 0 + (4m·s−^2 )t^2
8 s^2 = t^2
t = 2, 83 s

Step 7:Distance at half the time: Find an equation to relate the distance and
time
Half the time is 2 s, thus we have~vi,~aandt- all in the correct units.
We can use Equation 21.3 to get the distance:

∆~x = ~vit+^12 at^2

= (0m·s−^1 )(2s) +^12 (8m·s−^2 )(2s)^2
= 16 mEast

Exercise 21 - 7


1. A car starts off at 10 m·s−^1 and accelerates at 1 m·s−^2 for 10 s. What is its
final velocity?

Physics: Mechanics 429

Free download pdf