Everything Science Grade 11

12.3 CHAPTER 12. FORCE,MOMENTUM AND IMPULSE

Example 4: Newton’s First Law inaction

QUESTION

Why do passengers getthrown to the side when the car they are driving in goes around a

corner?

SOLUTION

Step 1 : What happens before the car turns

Before the car starts turning both the passengersand the car are travelling at the

same velocity. (picture A)

Step 2 : What happens while the car turns

The driver turns the wheels of the car, which then exert a force on thecar and

the car turns. This forceacts on the car but not the passengers, hence (by New-

ton’s First Law) the passengers continue movingwith the same original velocity.

(picture B)

Step 3 : Why passengers get thrown to the side?

If the passengers are wearing seat belts they will exert a force on the passengers

until the passengers’ velocity is the same as thatof the car (picture C). Without a

seat belt the passenger may hit the side of the car.

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A: Both the car and the

person travelling at the

same velocity

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B: The cars turns but not

the person

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C: Both the car and the

person are travelling at the

same velocity again