Physics, Physics, Physics

21 questions. 3)sab=4cm, tbc=1s, vac=sac/tac=9cm/3s=3cm/s

1) (2) (4) You are correct, I won't explain much, and I will default to your understanding.

22 questions. 1) As mentioned in the question, the reaction distance is the distance of the car's action within the reaction time, and the reaction time in this question is that the reaction distance is 15m s, which is very simple.

2) When the car walks to the crosswalk, the distance traveled by the person during this period is just within the range of the car, so it is possible to hit it.

3) Use questions to play freely. Hope.

1) Because the driver's reaction time is, and the original speed of 15m s is maintained during this time;

Reaction distance from v =

S car = V car T reverse = 15m s ;

2) The time it takes for a car to travel from a certain location to a pedestrian:

t total = t anti + t = ;

During this time, the distance traveled by pedestrians:

S person = V person T total =;

The front of the car ** is 3m away from the edge of the road, and the width of the car is, which shows that the car has the possibility of hitting pedestrians;

These topics are very basic, I hope you can read the book carefully, listen to the lecture carefully, review carefully, the time you ask on the Internet, if you can take it out to study, there must be improvement, not using your brain is not good to learn.

Within the elastic limit, the elastic force is proportional to the deformation, and the over-range elastic deformation is plastic deformation.

0---5 n

The elastic force is generated between the objects that are elastically deformed.

Occurs upwards.

He uses the method of "the same (time) ratio (displacement), and the referee determines that the person who reaches the finish line moves faster", and he uses the method of "same (displacement) to (time)".

Do it yourself who will help you with the exam.

Experimental process and derivation process: when the switch is disconnected, the current representation number is i1, when the switch is closed, the current representation number is i2, then the current through the resistor rx is i1, the current through the resistor r0 is i2-i1, according to the two resistors in parallel, the voltage at both ends is equal, rxi1=r0(i2-i1), and the resistance value of the resistance rx to be measured is:

rx=i1-i2/i1r0

1) There are 3 ropes connected to the movable pulley, and the suspect starts from the hook of the pure carrying wheel of the Wang pants manually.

2)p=fv=600n*(1．5m/10s)=90w

1. Pressure: The pressure at the bottom of the cup is the gravity of the water, 10N2 pressure: 10N 10N kg = 1kg, 100cm = 1

Solution: According to the formula of free fall: h=1 2*g*t2, g takes 10, so, t = seconds).

v=g*t=10*

I hope you understand the above answers, thank you!

h=1, 2gt; 2 g, if you take 10, t = root number, 2 v=gt; solution speed.