Answer:
The change in momentum of the two cars is equal and opposite
Explanation:
The change in momentum of an object is given by:
![\Delta p = m\Delta v](https://tex.z-dn.net/?f=%5CDelta%20p%20%3D%20m%5CDelta%20v)
where
m is the mass of the object
is the change in velocity
According to Newton Laws of motion, the force experienced by an object is equal to the rate of change of its momentum:
(1)
where
is the time interval during which the force is applied.
According to Newton's third law of motion, the force exerted by vehicle 1 on vehicle 2 during the collision is equal and opposite to the force exerted by vehicle 2 on vehicle 1. Therefore, we can write:
![F_1=-F_2](https://tex.z-dn.net/?f=F_1%3D-F_2)
Using (1), we can rewrite this as:
![\frac{\Delta p_1}{\Delta t}=-\frac{\Delta p_2}{\Delta t}](https://tex.z-dn.net/?f=%5Cfrac%7B%5CDelta%20p_1%7D%7B%5CDelta%20t%7D%3D-%5Cfrac%7B%5CDelta%20p_2%7D%7B%5CDelta%20t%7D)
Where
are the changes in momentum of car 1 and 2, and
is the duration of the collision. Simplifying, we get
![\Delta p_1 =-\Delta p_2](https://tex.z-dn.net/?f=%5CDelta%20p_1%20%3D-%5CDelta%20p_2)
So, the change in momentum of the two cars is equal and opposite.
Explanation:
We will calculate the gravitational potential energy as follows.
![P.E_{1} = mgz_{1}](https://tex.z-dn.net/?f=P.E_%7B1%7D%20%3D%20mgz_%7B1%7D)
= ![1000 kg/m^{3} \times 3 m^{3} \times 9.7 \times 40 m](https://tex.z-dn.net/?f=1000%20kg%2Fm%5E%7B3%7D%20%5Ctimes%203%20m%5E%7B3%7D%20%5Ctimes%209.7%20%5Ctimes%2040%20m)
= 1164000 J
or, = 1164 kJ (as 1 kJ = 1000 J)
Now, we will calculate the change in potential energy as follows.
![\Delta P.E = mg(z_{2} - z_{1})](https://tex.z-dn.net/?f=%5CDelta%20P.E%20%3D%20mg%28z_%7B2%7D%20-%20z_%7B1%7D%29)
=
= ![1000 \times 3 \times 9.7 (10 - 40)m](https://tex.z-dn.net/?f=1000%20%5Ctimes%203%20%5Ctimes%209.7%20%2810%20-%2040%29m)
= -873000 J
or, = -873 kJ
Thus, we can conclude that change in gravitational potential energy is -873 kJ.
This is a sneaky trick question, to help you discover whether you know
one of the differences between velocity and speed.
=======================================
If you make a list of the distances and directions, and ignore the times,
you find these:
4 - west, (3 + 1) - east . . . . . zero in the east/west direction
1.5 - north, 1.5 - south . . . . . zero in the north/south direction
This jogger went out, had a nice jog around the neighborhood,and ended up exactly where he started.
Average velocity = (distance between start point and end point) / (time)
IF the question asked for average SPEED, then you would need the total distance, and divide it by the total time. But it asks for VELOCITY, and <u>that</u> only involves the straight distance between the start point and the end point, regardless of the route taken in between.
The jogger ended up exactly where he started. The distance between start and end points was zero. Average velocity is (zero) / (time) . And that fraction is going to be <em><u>Zero</u></em>, no matter how long or how short the trip was, and no matter how much time it took.
The latent heat of vaporization for water is
2257 KJ per Kg . I'm pretty sure that's exactly
the same as 2257 joules per gram. So ...
When 1 gm of STEAM at 100 C condenses to
1 gm of liquid water at 100 C, it releases
2257 joules of heat energy to its environment.
In the x-direction, the frictional force is the lone force pro
tem on the player
The formula is: Fnet = ma
f = ma
In the y-direction, N, the normal force turns up and mg, the force of gravity turns
down
N = mg (since there is no speeding up in the vertical direction)
f = -uN
=> f = -umg
-umg = ma
=> a = -ug
Using the kinematics equation:
d = (vf^2 - vi^2) / 2a
d = vi^2 / 2ug
d = 4.6^2 / 2(4.508)
d = 2.35 m/s