Before the impact, let the velocity of the baseball was v m/s.
After being hit by the bat its velocity is -2v
So, change in velocity, Deltav=v-(-2v)=3v
Acceleration is defined as the rate of change in velocity, i.e. actual change in velocity divided by the time taken to change it. Time taken to change velocity is the time of actual contact of the bat and ball, i.e. 0.31 s.
a=(Deltav)/(Deltat)
=(3v)/0.37
Therefore, a/v=3/0.31=9.7 s^-1
So, the ratio of acceleration of the baseball to its original velocity is 9.7.
Given :
Initial speed , u = 0 m/s .
Final speed , v = 91 km/h = 25.28 m/s .
To Find :
a) Average acceleration .
b ) Assuming the motorcycle maintained a constant acceleration, how far is it from the traffic light after 3.3 s .
Solution :
a )
We know ,by equation of motion :
![v^2-u^2=2as\\\\a=\dfrac{v^2-u^2}{2s}\\\\a=\dfrac{25.28^2-0^2}{2\times 47}\ m/s^2\\\\a=6.8\ m/s^2](https://tex.z-dn.net/?f=v%5E2-u%5E2%3D2as%5C%5C%5C%5Ca%3D%5Cdfrac%7Bv%5E2-u%5E2%7D%7B2s%7D%5C%5C%5C%5Ca%3D%5Cdfrac%7B25.28%5E2-0%5E2%7D%7B2%5Ctimes%2047%7D%5C%20m%2Fs%5E2%5C%5C%5C%5Ca%3D6.8%5C%20m%2Fs%5E2)
b)
Also , by equation of motion :
![s=ut+\dfrac{at^2}{2}\\\\s=0+\dfrac{6.8\times (3.3)^2}{2}\ m\\\\s=37.02\ m](https://tex.z-dn.net/?f=s%3Dut%2B%5Cdfrac%7Bat%5E2%7D%7B2%7D%5C%5C%5C%5Cs%3D0%2B%5Cdfrac%7B6.8%5Ctimes%20%283.3%29%5E2%7D%7B2%7D%5C%20m%5C%5C%5C%5Cs%3D37.02%5C%20m)
Hence , this is the required solution .
Answer:
a. stay the same for very long
Explanation:
It is rare for any motion to stay the same for a very long time. The force applied on a body causes changes in the magnitude of motion.
- For motion to remain constant, there must not be a net force acting on the body
- All the forces on the body must be balanced.
- This is very hard to come by.
- Motion changes very frequently.
Answer:
The inventor of the electric cell was:
Alessandro Volta (in other words, Volta)
Explanation:
a) KE=0.5*mv^2==0.5*145*25^2=45312.5 J
b) PE=mgh=145*9.8*3.5=4973.5 J
c) ME=KE+PE=m(0.5v^2+gh)=62524 J