Answer:
(a) θ= 43.89°
(b) 

Explanation:
Ball 1:

Ball 2:

As the collision is elastic, it means that kinetic energy and momentum are conserved. Following that, we apply the law of conservation of energy and momentum:

and

Where u is the velocity before the collision, and v are the velocities after the collision. Both previous equations can be simplified as:

and

This because the two balls have the same mass. We know that the cue ball is deflected and makes an angle of 30°. From conservation in x-direction, we get::

and

Solving we get:

From conservation in y-direction, we get:

From this, we solve this equation system and get the answers. Remember to add 30° to the angle obtained.
Answer:
B. t = 0.250s
Explanation:
A. An image with the sketch of the bat emitting a sound, which reflects on a surface and return to the bat is attached below.
B. In order to calculate the time that the pulse emitted by the bat, return to the bat, you first calculate the time that pulse takes to arrive to the object.
You use the following formula:
(1)
x: distance to the object = 43m
t: time = ?
v: speed of sound beat = 343 m/s
You solve the equation (1) for t:

The time on which the bat hears the echo is twice the value of t, that is:

The time on which bat heart the echo of its sound, from the moment on which bat emitted it, is 0.250s
Answer:

Explanation:
Given that,
Force between two objects, F = 11.2 N
Distance between objects, d = 1.18 m
We need to find the charge on each objects. The force between charges is as follows :

So, the charge on each sphere is
.
Answer:
Using the pythagoras theorem
S²=9²+4²
S²=81+16
S²=97
S=9.85km.
In finding the direction
tan□=opposite/Adjacent
=4/9
□=23.96
¤=90-23.96
=66.03 degrees
9.85, N 66.03 E