Answer:
An excess of positive (or negative) charge causes the leaves to diverge
Bringing a neutral rod in the vicinity of the electroscope will cause some of the positive charge to leave the leaves (making the electrically neutral rod negative at the tip) causing the leaves to converge.
Explanation:
This is a good example of Doppler effect
Given
Source velocity Vs=20m/s
Apparent frequency Fa= 5.2 Hz
Recall speed of sound V=340m/s
The frequency of the horn Fh=?
But mathematically Fh=(V-Vs/V)*Fa
(340-20)/340*5.2=4.89Hz
Solution: 85.11 m
Given:
acceleration of the car, 
initial velocity,
final velocity, 
we need to find the displacement (s) of the car.
we would use the equation of motion:
hence, the displacement done by the car is = 85.11 m
Answer:
A very very big hole and some ramps
