Answer:
This depends on what angle they are approaching each other before they collided.The two simple cases are if they are running in the same direction or opposite direction from each other. For either case, use the conservation of momentum equation to solve: M_total*V_result = M1*V1 + M2*V2
Explanation:
Here are two possible solutions.
Head-on collision: M1=78, V1=8.5, M2=72, V2=-7.5 (that's negative because he's running the other way), M_total = 78+72 = 150, so V_result = (78*8.5 - 72*7.5)/150 = 0.82 m/s. Sanity check, they weigh about the same and so most of their velocity should cancel out.
Running the same way: change the sign of V2 to positive so V_result = (78*8.5 + 72*7.5)/150 = 8.02 m/s. Sanity check, they weigh about the same and the resultant speed is between the two starting velocities.
<em>hope it helps:)</em>
The vertical component is B) 7.9 m/s
Explanation:
A vector can be resolved into its horizontal and vertical components. The horizontal and the vertical components form the sides of a right triangle, in which the resultant corresponds to the hypothenuse, so we can use Pythagorean's theorem:

where
R is the resultant vector
Rx is the horizontal component
Ry is the vertical component
In this problem, we have:
R = 12 m/s is the resultant vector
Rx = 9 m/s is the horizontal component
Solving the formula for Ry, we find the vertical component:

Learn more about vector components:
brainly.com/question/2678571
#LearnwithBrainly
Answer:
Explanation:
The best way to do this is to remember the rule about the halfway mark in a parabolic path. At a trajectory's half way point in its travels, it will be at its max height. To get the total time in the air, we take that time at half way and double it. Here's what we know that we are told:
initial velocity is 20 m/s
Here's what we know that we are NOT told:
a = -9.8 m/s/s and
final velocity is 0 at an object's max height in parabolic motion.
We will use the equation:
where v is final velocity and v0 is initial velocity. Filling in:
0 = 20 + (-9.8)t and
-20 = -9.8t so
t = 2 seconds. The stone reaches its max height 2 seconds after it is thrown; that means that after another 2 seconds it will be on the ground. Total air time is 4 seconds.
Number 4 is : a light hour is a measure of time in space used to calculate the length of time between one object to another and one light hour equals 1.079 × 109 kilometers or 1.079e+9
Answer:
It is because the room is occupied with stuffs.
Explanation:
In a well furnished room there are things
like bed, cupboard, wardrobe and other stuffs, So they act as absorbing materials.
They absorb sound and do not give a chance to resounds.