Newton's laws help please?

Can someone please slowly walk me through this

If the box was initially at rest, shouldn't it stay at rest when the car accelerates so "appear to move backwards" and fall to the ground ? This means that the distance from the edge of the truck and the box decreases until it falls.

Does Mary not observe this ? 

The book says, to Mary, the box does not move ? How doesn't it move, shouldn't it fall ? 

I'm limited by english so I want to ask, "moves towards the rear of the truck" means what ? The open end of the truck ? Or towards the front seats ?

I also have no idea how to think about from Chris's frame of reference.

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2 Answers

  • Vaman
    Lv 7
    1 month ago

    Reference frame is the coordinate system from which you.

    1 coordinate system. It is based in you. You see car moving and box moving.

    2. If you are sitting on the box, then you will see only car moving.

    3. If you are driving, do not lookout. You will see box moving backward.

    These three are valid frame of reference.

    ff you are sitting in the car and c

    Chris is on the ground, you will see Chris moving backward. At the same time, Chris sees you moving away. Reference system, you have to define.

  • Lôn
    Lv 7
    1 month ago

    As there is no friction on the back of the lorry then when the lorry moves forward, the box remains where it is so if at the beginning , the box is near the cab, when the lorry moves forward the box 'appears' to move to the back of the lorry. However, if Mary is standing opposite the box the box doesn't appear to move, the lorry moves forward until the box falls off the back.

    The rear means the back...AWAY from the seats.

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