# Physics

posted by .

I'm learning about Newton's Laws of Motions and I'm having trouble understanding these questions:

"A rear-end collision between a soft-drink truck and a car occurs. The truck driver claims the car backed into him, while the auto driver claims that the truck hit him from behind. The only evidence is that quite a number of soft-drink bottles fell forward in the truck. From the evidence, can you tell who was at fault?"

I think it's a car's fault, because if the truck moved forward (and hit the car), then the bottles would have fell backwards...

"What is the principle behind a magicians ability to pull a tablecloth from beneath china and glassware without breaking them?"

I'm assuming this has to do with Newton's 1st Law, and how objects that aren't moving don't want to move.

"Explain why when you walk on a log floating in water, the log moves backward as you move forward."

This one I don't know how to explain.

• Physics -

#1 The truck was behind the car. If the bottles in the truck fell forward, it suddenly accelerated backwards. This would happen if the car backed into it or if the truck rear-ended the car. You can't tell which happened.

#2 Yes, Newton's first law is involved.

#3 There is negligible friction between log and water. The center of mass of the man-plus-log system stays in the same place. If the man moves in one direction, the log must move in the opposite direction to keep, the center of mass in the same place. (You could also invoke Newton's third law).

## Similar Questions

1. ### physics

A car is behind a truck going 23.0 m/s on the highway. The driver looks for an opportunity to pass, guessing that his car can accelerate at 2.2 m/s2, and he gauges that he has to cover the 24.0 m length of the truck, plus 10 m clear …
2. ### physics

Q2. A box rests on the (frictionless) bed of a truck. The truck driver starts the truck and accelerates forward. The box immediately starts to slide toward the rear of the truck. Discuss the motion of the box, in terms of Newtonâ€™s …
3. ### scienc

I'm driving my car of mass 1000 kg at 100 km/hr when I accidentally hit the rear end of a truck of mass 5000 kg traveling in the same direction at 90 km/hr. My car and the truck lock together and move as a single object. Let F1 be …
4. ### physics

A truck is pulling a car. FT is the magnitude of the force that the truck exerts on the car FC is the magnitude of the force that the car exerts on the truck Consider the following scenarios independently. 1)The truck is driving with …
5. ### Physics

Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this?

Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this?
7. ### College Physics

Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this?
8. ### Physics >.<

A big truck has a mass of 5,000kg. It is moving down the road at a velocity of 15m/s. As it approaches a stop sign, the driver tries to stop, but the truck slides on ice and hits a car (mass = 500kg) that is stopped. After the collision, …
9. ### physics

The driver of a car wishes to pass a truck that is traveling at a constant speed of 19.0 m/s . Initially, the car is also traveling at a speed 19.0 m/s and its front bumper is a distance 24.3 m behind the truck's rear bumper. The car …
10. ### Physics

A car is behind a truck going 18 m/s on the highway. The car's driver looks for an opportunity to pass, guessing that his car can accelerate at 0.6 m/s2 and that he has to cover the 20-m length of the truck, plus 10-m extra space at …

More Similar Questions