I believe the answer is free electrons
Answer:

Explanation:
Speed experimented by the ball before and after collision are determined by using Principle of Energy Conservation:
Before collision:


After collision:


The magnitude of the impulse delivered to the ball by the floor is calculated by the Impulse Theorem:
![Imp = (0.32\,kg)\cdot [(17.153\,\frac{m}{s} )-(-19.304\,\frac{m}{s} )]](https://tex.z-dn.net/?f=Imp%20%3D%20%280.32%5C%2Ckg%29%5Ccdot%20%5B%2817.153%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29-%28-19.304%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5D)

Answer:
a) F = μk mg Cosθ
b) F = 279.78 N
Explanation:
a) F = μk R
Based on the description in the question, the horizontal reaction is:
R = mg Cosθ
The force required to move the box with constant speed in terms of m, μk, θ, and g is :
F = μk mg Cosθ
b) If m = 90 kg
g = 9.8 m/s²
μk=0.35
θ = 25⁰
Force required to slide the 90-kg patient across a floor at constant speed by pulling on him at an angle of 25∘ above the horizontal will be:
F = μk mg Cosθ
F = 0.35 * 90 * 9.8 * cos25
F = 279.78 N
Answer:
11760J
Explanation:
Given parameters:
Height of hill = 30m
Weight = 40kg
Unknown:
Gravitational potential energy = ?
Solution:
To find the gravitational potential energy, it is the energy due to the position of a body;
G.PE = mgh
m is the mass
g is the acceleration due to gravity
h is the height
Now insert the parameters and solve;
G.PE = 40 x 9.8 x 30 = 11760J
I sort of understand but what does it mean by.... Another?