Answer:
Explanation:
Given
Initial velocity of ball 
height of window 
Using Equation of motion
where u=initial velocity
t=time
a=acceleration
As ball is already is at a height of 20 m so
(b)highest point is obtained at v=0
where
v=final velocity
u=initial velocity
a=acceleration
s=displacement
Highest Point will be 
(c)Time taken when the ball hit the ground i.e. at Y=0
impact velocity 
Answer: a) 0.11 Amp b) 0.000429 Joules c) 0.000514 watt
Explanation:
a)current
I=V/r I=6.0/550 =1.1*10^-2 A
b) energy
E= 1.1*10^-2 x (6.0) x 0.00065s(<-- remember to convert ms to seconds) = 0.000429J
C) Average power
P = (0.000429 x 72) / 60
P = 0.000514 W
Answer:
Intermolecular forces
Explanation:
The force of attractions that act between molecules are called intermolecular forces.
Their nature is electromagnetic, this means that they are just an expression of the electromagnetic force.
One example of intermolecular force is the ionic bond: this type of bond occurs when there are two ions, one positively charged and the other one negatively charged, and they are attracted by each other due to the electrostatic force, which therefore creates a bond between them.
Other types of intermolecular forces include:
Hydrogen bond
Ion-dipole forces
Van der Waals forces
The strength of these intermolecular forces determine the state of the substance. In fact, in solids, these forces are very strong, so that the molecules are strongly bond to each other and they cannot move freely, but only vibrate about their fixed position. On the other hand, in gases, these forces are very weak, therefore the molecules are able to move freely away from each other.
The ideal concept for solving this question is based on the Doppler effect, for which it is indicated that the source's listening frequency changes as the distance and the relative speed between the receiver and the transmitter are also changed. However, if the relative velocity between the two objects is zero as in the particular case presented (since both travel at 75km / h) we have that there will be no change in frequency.
Therefore the frequency that I hear and that my sister would listen would be the same.
