To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.
Gravitational potential energy can be defined as

As M=m, then

Where,
m = Mass
G =Gravitational Universal Constant
R = Distance /Radius
PART A) As half its initial value is u'=2u, then



Therefore replacing we have that,

Re-arrange to find v,



Therefore the velocity when the separation has decreased to one-half its initial value is 816m/s
PART B) With a final separation distance of 2r, we have that

Therefore




Therefore the velocity when they are about to collide is 
Answer:
a.Distance = 150 m
b. Displacement = 50 m
Time lapsed = 5 seconds
Explanation:
a. Distance is the change in the position of an object.
The distance covered by the car = 100 + 50
= 150 m
b. Since displacement is a vector quantity,
Displacement of the car = 100 - 50
= 50 m due east
c. Time elapsed is the time taken for the motion of the car starting from when its starts to when it stops.
Thus, the time elapsed = 4 + 1
= 5 seconds
Answer:
7.5 m
Explanation:
= initial speed of the ball = 8 m/s
= angle of launch = 40° deg
Consider the motion along the vertical direction :
= initial velocity along vertical direction =
= 8 Sin40 = 5.14 m/s
= acceleration along vertical direction = - 9.8 m/s²
= time of travel
= vertical displacement = - 1 m
Using the kinematics equation


= 1.22 sec
Consider the motion along the horizontal direction :
= initial velocity along horizontal direction =
= 8 Cos40 = 6.13 m/s
= acceleration along vertical direction = 0 m/s²
= time of travel = 1.22 sec
= horizontal displacement = ?
Using the kinematics equation


= 7.5 m
Answer:
Explanation:
To find Sammy's course you have to add the two velocities (vectors), 18 mph 327º and 4 mph 60º.
To add the two vectors analytically you decompose each vector into their vertical and horizontal components.
<u>1. 18 mph 327º</u>
- Horizontal component: 18 mph × cos (327º) = 15.10 mph
- Vertical component: 18 mph × sin (327º) = - 9.80 mph

<u>2. 4 mph 60º</u>
- Horizontal component: 4 mph × cos (60º) = 2.00 mph
- Vertical component: 4 mph × sin (60º) = 3.46 mph

<u>3. Addition:</u>
You add the corresponding components:

To find the magnitude use Pythagorean theorem:
<u>4. Direction:</u>
Use the tangent ratio:
Find the inverse: