Everything Science Grade 10

CHAPTER 21. MOTION IN ONE DIMENSION 21.7

We are given:

~vi = 10m·s−^1

∆~x = 725m

t = 10s

~a =?

Step 2: Find an equation of motion relating the given information to the

acceleration

If you struggle to find the correct equation, find the quantity that is not

given and then look for an equation that has this quantity in it.

We can use Equation 21.3

∆~x=~vit+^12 ~at^2

Step 3:Substitute your values in and find the answer

∆~x = ~vit+^12 ~at^2

725 m = (10m·s−^1 × 10 s) +^12 ~a×(10s)^2

725 m− 100 m = (50s^2 )~a

~a = 12, 5 m·s−^2

Step 4:Quote the final answer

The racing car is accelerating at 12,5 m·s−^2 North.

Example 8: Equations of motion I

QUESTION

A motorcycle, travelling East, starts from rest, moves in a straight line with a con-

stant acceleration and covers a distance of 64 m in 4 s. Calculate

Physics: Mechanics 427